HK1181202B

HK1181202B - Test station for wireless devices and methods for calibration thereof

Info

Publication number: HK1181202B
Application number: HK13108374.4A
Authority: HK
Inventors: Rada Patrick; Patton Ruska
Original assignee: Emscan Corporation
Priority date: 2011-12-06
Filing date: 2013-07-16
Publication date: 2017-10-06

Abstract

A test station for wireless devices and methods for calibration thereof. The test station includes a signal generator, a calibrator, a scanner having receiving and transmitting antennas, a signal analyzer, and a computer. Under the direction of the computer, the signal generator generates a calibration signal in accordance with a programmable calibration signal script. The calibrator may be used to emulate either a wireless device in transmit mode by transmitting the calibration signal to the scanner for analysis by the signal analyzer, or a wireless device in receive mode by receiving the calibration signal from the scanner for analysis by the signal analyzer. The behavior of the test station is calibrated by correlating signal parameters of the calibration signal as specified by the calibration signal script and as measured at the signal analyzer.

Description

Test station for wireless devices and calibration method thereof

Technical Field

The present invention relates to a test station for wireless devices, and a method for calibrating the same.

Background

During the manufacture of wireless devices, such as cellular telephones, that transmit and/or receive Radio Frequency (RF) signals, the wireless devices are tested at designated test stations on the manufacturing line to ensure that the devices meet performance parameters related to the transmit or receive function. Conventional test stations for wireless devices have fixtures configured to hold a Device Under Test (DUT) in a particular position during testing, while probes will establish one or more propagating (wired) physical connections with the DUT. The acceptable devices will be accepted and assembled and the unacceptable devices will be rejected and serviced. Devices at the pass and fail edges may be retested once or twice to confirm that they passed. In order to maximize manufacturing efficiency and profitability, testing should ideally take as little time as possible. This is particularly important for Original Design Manufacturers (ODMs) because their profitability is related to optimizing production time.

A reference wireless device, commonly referred to as a Golden Unit (GU), with known transmission or reception capabilities, may be used to calibrate and verify the calibration of the test station. The GUs may also be used to confirm the test results of the DUT or to determine that there is a bias in the DUT test results. For example, if two or more consecutive DUTs fail testing, the GUs can be used to test and compare the test results to find problems in the DUT production process, e.g., having a failed component in the DUT or the test rig testing is not accurate enough. For more levels and to verify the calibration of the test bench more thoroughly, a combination of GUs of several different standards may be employed, such as "just passed" GUs (i.e., units just in an acceptable range that consistently pass the test) and "just failed" golden units (i.e., units just in an unacceptable range that consistently fail the test).

There are several potential disadvantages because the conventional test station of the wireless device needs to establish a conductive connection with the DUT and also uses to the GU. The physical connection between a test station and a DUT or GU typically requires custom-made fixtures and probes associated with a conventional test station and is therefore limited to a particular DUT type (e.g., a particular make and model of cellular phone) or GU. Furthermore, the DUT or GU may need to be accurately positioned within the test station by mechanical guides. Therefore, building test stations that are specific to a particular DUT type, and reconfiguring test stations for different DUT types, requires a great deal of effort, time, and money. In addition, the new test fixture and associated software may need to be installed in place on the old test fixture and subject to inspection and calibration. Fast testing of MIMODUT with multiple inputs/multiple outputs can be extremely complex. Physical connection and disconnection of DUTs or GU can cause both the test station and the DUTs or GU to wear out. Finally, it is difficult to manufacture many GUs and maintain them at the desired performance levels. It is particularly difficult to manufacture and maintain "just passed" or "just failed" GUs to verify the calibration at the passing and failing edges, respectively.

There is therefore a need in the art to develop systems and methods relating to calibration of test benches that alleviate the disadvantages of the prior art. Preferably, such a system and method would eliminate the need to establish a conductive physical connection between the test station and the DUT and use a dedicated GU.

Disclosure of Invention

In one aspect, the present invention provides a method for calibrating a test station for testing a wireless device in a transmission mode, the test station comprising a receiving antenna, a calibrator having a calibrator antenna, a signal generator, and a signal analyzer, the method comprising the steps of:

(a) providing a signal path, the signal path comprising: a conductive path from the signal generator to the calibrator antenna, a wireless path from the calibrator antenna to the receive antenna, and a conductive path from the scanner antenna to the signal analyzer;

(b) providing calibration signal script code for a calibration signal having a target transmission power level at the calibrator antenna;

(c) generating a calibration signal through the signal channel using the signal generator;

(d) measuring a power level of the calibration signal using a signal analyzer; and

(e) correlating a target transmission power level of the calibration signal with a measured power level of the calibration signal.

In a specific embodiment, the calibration signal script further specifies one or more of the following parameters of the calibration signal: frequency; modulation and data rate; an error vector magnitude; spectral mask and uniformity; the occupied bandwidth is obtained; phase noise; I-Q imbalance; a clock frequency offset; a center frequency leak; or sequencing.

In another aspect, the present invention provides a test station for testing a wireless device in a transmit mode, the test station comprising:

(a) a signal generator for generating a conducted calibration signal;

(b) a calibrator including at least one calibrator antenna conductively coupled to the signal generator for wireless transmission of the calibration signal;

(c) a wireless scanner comprising a receive antenna for wirelessly receiving the calibration signal;

(d) a signal analyzer conductively coupled to the receive antenna to receive and measure a power level of the calibration signal;

(e) a computer, comprising:

(i) a memory for storing a calibration signal file encoding a calibration signal having a target transmission power level at the calibrator antenna, and a set of program instructions for implementing the method of the present invention;

(ii) a processor operatively connected to the memory, the signal generator; and the signal analyzer, the processor configured to execute the set of program instructions.

In an embodiment, the calibrator further comprises a housing for protecting the calibrator antenna, which is conductively connected with the signal generator via a calibrator signal path, wherein the calibrator signal path comprises:

(a) a port selectively conductively connectable with the signal analyzer;

(b) a calibrator antenna switch to selectively connect the calibrator antenna to the calibrator signal path and disconnect the port from the calibrator signal path, or disconnect the calibrator antenna from the calibrator signal path and connect the port to the calibrator signal path.

In another aspect, the present invention provides a method of calibrating a test station for testing a wireless device in a receive mode, the test station including a transmit antenna, a calibrator having a calibrator antenna, a signal generator, and a signal analyzer, the method comprising the steps of:

(a) providing a signal path comprising a conductive path from the generator to the scanner antenna, a wireless path from the transmit antenna to the calibrator antenna, and a conductive path from the calibrator antenna to the signal analyzer;

(b) providing a calibration signal script encoding for a calibration signal having a target received power level and a corresponding target BER at the signal analyzer;

(c) generating a calibration signal through the signal path using a signal generator;

(d) setting a power level of a calibration signal received at the signal analyzer to a target received power level;

(e) measuring a BER of a calibration signal received at the signal analyzer;

(f) varying, if necessary, the power level of the calibration signal generated by the signal generator to converge the measured BER towards a target BER;

(g) the target received power level and the target BER are correlated with a calibration signal power level generated by a signal generator where the measured BER converges towards the target BER.

In yet another aspect, the present invention provides a test station for testing a wireless device in a receive mode, the test station comprising:

(a) a signal generator for generating a conducted calibration signal;

(b) the wireless scanner comprises a transmitting antenna which is in conductive connection with the signal generator so as to wirelessly transmit the calibration signal;

(c) a calibrator comprising at least one calibrator antenna for wirelessly receiving the calibration signal;

(d) a signal analyzer conductively coupled to the calibrator antenna to receive and measure a power level of the calibration signal;

(e) generator signal amplitude varying means operatively connected to said signal generator for varying the amplitude of the calibration signal generated by said signal generator;

(f) analyzer signal amplitude varying means operatively connected to said signal analyzer for setting the amplitude of a calibration signal received by said signal analyzer;

(g) BER measuring means operatively connected to the signal analyzer to measure the BER of the calibration signal received by the signal analyzer;

(h) a computer, comprising:

(i) a memory for storing a calibrated signal file encoding a calibration signal having a target received power level and corresponding target BER at the signal analyzer, and a set of program instructions for implementing the method of claim 10;

(ii) a processor operatively connected to the memory, the signal generator, the signal analyzer, the generator signal amplitude altering device, the analyzer signal amplitude altering device, and the BER measuring device, the processor configured to execute the set of program instructions.

Drawings

In the drawings, like elements have like reference numerals. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, each embodiment shown represents only one of several possible arrangements using the basic concepts of the invention. In the drawings:

FIG. 1A shows a schematic view of one embodiment of a test station of the present invention.

FIG. 1B shows a physical implementation of an embodiment of the test station shown in FIG. 1A.

FIG. 2 shows a schematic flow chart of one embodiment of a method for testing a DUT using the test station of the present invention.

Figure 3A shows a schematic diagram of an embodiment of the calibrator of the present invention.

FIG. 3B shows a schematic diagram of the test rig shown in FIG. 1B, wherein the calibrator functions as a GU simulator.

FIG. 4 shows a schematic flow chart of an embodiment of the calibration method of the present invention for calibrating a test stand of the present invention for a DUT in transmit mode.

Fig. 5 shows a schematic circuit diagram of an embodiment of the test bench of the invention for calibrating the test bench for temperature effects.

FIG. 6 illustrates a flow chart of an embodiment of a calibration method for calibrating a test rig as shown in FIG. 5 for temperature effects.

Fig. 7 shows a schematic circuit diagram of an embodiment of the test bench of the invention for calibrating the test bench for temperature effects.

FIG. 8 illustrates a flow chart of an embodiment of a calibration method for calibrating a test rig as shown in FIG. 7 for temperature effects.

Fig. 9 shows a flow chart of a method for preparing a calibration signal file.

Fig. 10 shows a circuit schematic of the auto-detection circuit of an embodiment of the calibrator of the present invention.

11A-11D illustrate a flow chart of an embodiment of a method for calibrating a test stand of an embodiment of the present invention.

Fig. 12 shows an example of the self-calibration calculation of the test station of the present invention.

Fig. 13A to 13K show a number of circuit schematics and accompanying calibration calculation examples for calibrating the test bench of the present invention for signal power loss due to cable insertion effects.

Fig. 14A to 14E show a number of circuit schematics and accompanying calibration calculation examples for calibrating the test bench of the present invention for conducted signal loss.

Figures 15A to 15C show a schematic circuit diagram of an embodiment of a test station when calibrated using GU.

Detailed Description

The present invention relates to a system and method for calibrating a test station for a wireless device. In describing the present invention, all terms not defined herein are to be given their ordinary meaning as recognized in the art. The following description is of specific embodiments or specific uses of the invention and is intended to be illustrative only and not to limit the scope of the invention, which is defined by the claims. The following description is intended to cover all alternatives, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims.

As used herein, the term "wireless device" refers to any device (regardless of power or range) that transmits, receives, or both transmits and receives signals in the form of electromagnetic radiation. The wireless device may employ various configurations and protocols such as, but not limited to, cellular telephone, WiFi, WiMax, bluetooth, Zigbee, and the like. In one embodiment, the wireless device comprises a cellular telephone having both Bluetooth and WiFi antennas.

As used herein, the term "device under test" or "DUT" refers to a wireless device that is undergoing testing by a wireless device test station for either wireless transmit or receive functionality, or both.

One aspect of the present invention provides a test station including a wireless calibrator. Fig. 1A and 1B show an embodiment of a test bench (5) of the invention, which will be described below. The test station (5) includes a scanner (10), an input/output module (12), a test module (14), a computer (15) running test software, a calibrator (16), and optionally a temperature sensor (not shown). Wherein the scanner (10) comprises a receiving and/or transmitting antenna, or an array of a plurality of receiving and/or transmitting antennas.

The antenna of the scanner (10) detects wireless signals emitted by DUTs, GUs or calibrators (16). In one embodiment, the scanner (10) includes transmitting and detecting wireless communicationsThe antenna probe array (101) of numbers, an RF switch (102) connected to an RF input/output port (103), a receiver (104) for receiving signals detected by the antenna probe array (101), and a data control module (105) connected to a computer (15) through a USB interface. The antenna probe (101) may emit a wireless signal generated by the computer (15) or by the test module (14). The scanner (10) may be enclosed in a protective box or chamber (11) that is resistant to electromagnetic radiation, but a protective box or chamber is not necessary, for example if the external electromagnetic radiation level is sufficiently low so as not to affect any test results. In one embodiment, the scanner (10) is a near field scanner (10), such as, for example, RFxpert, as a non-limiting example^TMScanner board (Emscan, Calgary, Alberta) or near field scanner described in the applicant's invention entitled "multi-channel non-absorptive near field measurement system" (U.S. patent No. 7,672,640 and co-pending patent application No. 2007/0285322), which are incorporated by reference herein in their entirety where licensed.

The input/output module (12) serves as a conducted signal interface between the test module (14) and the scanner (10), and between the test module (14) and the calibrator (16). In one embodiment, as shown in fig. 1A and 1B, these conducted signals are transmitted through coaxial cables #2 and #3 and SMA connectors between the test module (14) and the input/output module (12), and coaxial cable #1 and SMA connectors between the test module (14) and the calibrator (16). The cables #1, #2, and #3 may be made of one cable or several cables connected in series. The input/output module (12) preferably includes one or more low noise, low distortion power amplifiers (a1) so that the scanner (10) or calibrator (16) can emit wireless signals at levels comparable to DUTs (as described below).

The test module (14) includes a signal generator for generating a conducted signal and a signal analyzer for receiving the conducted signal. The test module (14) is operatively connected to the computer (15) via a standard USB. MeasuringThe test module (14) may include means, such as, by way of non-limiting example, a LitePointIQ2010^TMA tester (LitePoint corporation, california, usa) having a Vector Signal Generator (VSG) for the signal generator and a Vector Signal Analyzer (VSA) for the signal analyzer. A typical VSA analyzes the physical layer integrity of a signal by parameters such as power level, Error Vector Magnitude (EVM), Occupied Bandwidth (OBW), spectral mask, residual center frequency leakage, subcarrier, frequency offset, and the like, as well as parameters known to those skilled in the art.

The computer (15) has a memory for storing calibration and test software and calibration software scripts and also has a processor for executing the calibration and test software. A computer (15) is operatively connected to the VSG, VSA, scanner (10), and may be further connected to the calibrator (16) by a USB interface.

The calibrator (16) may simulate GU in transmit mode by transmitting wireless signals generated by the VSG to the scanner (10) for conducted transmission to the VSA under the direction of the computer (15). Alternatively, the calibrator (16) may emulate the GU in receive mode by receiving wireless signals generated by the VSG from the scanner (10) under the direction of the computer (15). The calibrator (16) can be used with the system (within the technical limits of the components) to simulate any standard (e.g., "good", "bad", "just qualified", or "just unqualified", etc.) for any type of DU or GU, since the signals transmitted or received by the calibrator (16) are generated by the VSG under the direction of the computer (15) and the signal parameters can be programmed at the user's discretion.

Fig. 3A shows a schematic diagram of an embodiment of the calibrator (16). The calibrator (16) includes a calibrator antenna (160) that may be conductively connected to the input/output module (12) through the printed circuit board via port P4. The calibrator antenna (160) transmits and receives wireless signals at different frequencies. For example, frequencies may include WLAN2.4 and 5GHz bands and 802.11b, g, a, and n, with bandwidths of 20MHz and 40 MHz. In one embodiment, the calibrator antenna (160) is a dual band antenna (160). The dual band antenna (160) is preferably a balanced antenna that is less susceptible to nearby ground planes, components, and microphone noise and is more omni-directional than a single band antenna. The calibrator (16) may further include a port P6, a switch SW6, a USB interface (164), a calibrator memory (166), and an indicator (168). Port P6 may be selectively connected to the input/output module (12) or disconnected from the input/output module (12) via port P5 under the direction of the computer (15), the USB interface (164) selectively switches switch SW6, to conductively connect the calibrator antenna (160) or port P6 to port P4. the usb interface (164) also controls the indicator (168), to indicate the connection status of the calibrator (e.g., whether port P6 is connected to port P5) and the signal transmission status of the calibrator (16) (e.g., whether the calibrator (16) is transmitting or receiving wireless signals), hi one embodiment, the indicator (168) is a multi-color led the memory (166) may be used to store a set of software instructions for controlling text, signal parameters for calibrating the system, and a unique identifier for selecting an appropriate calibration file and avoiding confusion.

Fig. 3B shows an embodiment of the calibrator (16) physically connected to the input/output module (12) via coaxial cable # 1. The calibrator may include a plastic case enclosing a calibrator antenna (16) sized approximately equal to the size of a typical cellular telephone. The position of the antenna (16) within the box may be marked outside the box to facilitate proper placement of the aligner (16) on the scanner (10). Preferably, the calibrator (16) remains connected so that the test bench (5) can be calibrated quickly and easily even during production without causing additional wear of the test bench (5).

In one embodiment, the system further comprises a temperature sensor (not shown) operatively connected to the computer for monitoring temperature changes of components of the system (5), the performance of each of the components being affected by the temperature changes. More levels (moregranularity) can be obtained by placing temperature sensors in different areas of the test bench (5) respectively.

An embodiment of the use and operation of the test bench (5) will now be described by way of example with reference to the system embodiment shown in fig. 5, and the following stages:

and (B) stage A: preparing a calibration signal file;

and (B) stage: self-calibration (optional) of the test module (14);

and C: the test bench (5) is calibrated for the insertion loss and the conduction loss of the cable;

and stage D: the test station (5) calibrates the combined conduction and wireless signal losses for the DUT in transmit and receive modes;

and a stage E: the test bench (5) is calibrated (optional) for temperature influence;

and F: the test bench (5) is calibrated (optional) by utilizing GU;

stage G: the test bench (5) uses the calibrator (16) as a simulator for calibration (optional); and

stage H: and testing the DUT.

The following examples are provided only for illustrating exemplary embodiments of the present invention and are not to be construed as limiting the invention as defined by the claims.

And (B) stage A: a calibration signal script is prepared. The calibration signal script encodes information about signal parameters of a calibration signal to be generated in a subsequent calibration phase. FIG. 9 illustrates an exemplary process of preparing a calibration signal script. The calibration signal script may be generated manually or automatically in spreadsheet form and then stored in the memory of the computer (15) or the memory (166) of the calibrator (16). For example, as described further below, when the calibrator (16) is used to emulate GUs in transmission mode, the calibration script may contain information about the power level of the calibration signal to be transmitted by the calibrator antenna (16). When the calibrator (16) is used to emulate GUs in receive mode, the calibration script may contain information about the target sensitivity level of the GUs' target BER. Other signal parameters that may be encoded include: (a) a transmission level of a unit frequency; (b) modulation and data rate; (c) correlation signal integrity as measured by an Error Vector Magnitude (EVM) parameter; (d) frequency mask and uniformity; (e) occupied Bandwidth (OBW); (f) phase noise and IQ imbalance; (g) a clock frequency offset; and (h) center frequency leakage. The calibration script file may also encode information about: a test installation of DUT or DUT type; an identification number; a software version; a WLAN chipset driver version; a date; distance from the scanner plate.

Once the calibration signal script is ready, the calibration flow may continue. Figures 11A to 11D show an embodiment of a calibration procedure for the embodiment of the test bench (5) shown in figure 5. The calibration flow starts by reading a prepared calibration signal script from a computer (15) (step 1101). In the preferred embodiment, the calibration procedure is performed once for each DUT type with minimal manual handling of hardware and cabling. It will be appreciated that all calibration steps can be performed automatically under the direction of the computer (15) to control the various components and store information, and that there is little need for the user to manually handle the test stand (5) or perform calculations.

And (B) stage: self-calibration (optional) of the test module (14). The calibration of the test module (14) is verified (FIG. 11A: step 1102). The VSG is conductively connected to the VSA using only signal paths within the test module (14). The VSG generates a signal according to the calibration test script. FIG. 12 shows an example of the test module self-calibration calculation. The self-calibration factor (L columns) is calculated as the difference between the power level of the signal generated by the VSG (J columns) and the power level of the signal received by the VSA (K columns). The self-calibration factor is stored and is ready for use in a subsequent calibration step, in particular to add it to the power level of the signal to be generated by the VSG.

And C: the test bench (5) is calibrated for cable insertion loss. The test station (5) calibrates for the cable insertion loss of cables #1, #2 and #3 (FIG. 11A, step 1103-. Generally, the method of performing calibration is to sequentially establish a plurality of conducted signal paths from the VSG to the VSA via a cable, generate a signal having a known power level using the VSG according to a calibration signal script passing through the paths, measure the power level of the signal at the end of the signal path using the VSA, and calculate the power level difference of the signal at the VSG and VSA after accounting for other power losses. The calibrator (16) is configured to form portions of the conducted signal path, as described below.

The combined insertion loss of cable #2 and cable #3 is determined (step 1103). The computer (15) switches the connection to establish a signal path through both cables #2 and #3, as highlighted by an "x" in fig. 13A. The VSG generates a signal according to the calibration signal script. The signal is received by the VSA and measured and temporarily stored. FIG. 13B illustrates a combined calculation of cable insertion loss, IL, for cables #2 and #3 according to the following equation_23m(f) (in all equations, the variable f is the frequency of the signal) (step 1110):

IL_23m(f)＝L_VSG(f)-L_VSA(f)-IL_P3-_P2(f) (formula 1)

Wherein:

L_VSG(f) the method comprises the following steps Level (dB) of programmed and calibrated signals emitted by VSG

L_VSA(f) The method comprises the following steps Level (dB) of measured signal received by VSA

IL_P3-_P2(f) The method comprises the following steps The insertion loss from port P3 to P2 was previously measured at various frequencies in factory calibration (dB).

Here, all levels (L) are given in dB and refer to milliwatts (dBm).

Next, the approximate insertion loss of cable #3 is determined (step 1104). The computer (15) switches the connection to establish a signal path through cable #3 (but not cable #2), as highlighted by an "x" in fig. 13C. The VSG generates signals of the same signal channel according to the calibration signal script. The signals are received by a scanner (10), measured and temporarily stored. FIG. 13D illustrates how the approximate insertion loss, IL, of cable #3 is calculated according to the following equation_3m(f) + (f) (step 1110):

IL_3m(f)+(f)＝L_VSG(f)-L_RF×RX(f) (formula (II)2)

Wherein:

L_VSG(f) the method comprises the following steps The level (dB) of the programmed and calibrated signal emitted by the VSG;

L_RF×RX(f) the method comprises the following steps The level (dB) of the measurement signal received by the scanner (10).

Next, the approximate insertion loss of cable #2 is determined (step 1105). The computer (15) switches the connection to establish a signal path through cable #2 (but not cable #3), as highlighted by "x" in fig. 13E. The VSG generates signals through the signal path according to the calibration signal script. The signals are received by a scanner (10) and measured and temporarily stored. FIG. 13F illustrates calculating an approximate insertion loss value, IL, for cable #2 according to the following equation_2m(f) + (f), (step 1110):

IL_2m(f)+(f)＝L_VSG(f)-L_RF×RX2m(f) (equation 3)

Wherein:

L_RF×RX2m(f) the method comprises the following steps The level (dB) of the measurement signal received by the scanner (10).

From the values determined above, IL is more accurately calculated_23m(f)、IL_2m(f) + (f) and IL_3m(f) Insertion loss of Cable #2, IL_Cable#2(f) And insertion loss, IL, of Cable #3_cable#3(f) Fig. 13G illustrates the calculation of these values by solving the following equations in the case of "excluding" any potentially inaccurate factors or frequency variations in the sensor (10) (step 1110):

IL_Cable#8(f)+IL_Cable#2(f)＝IL_23m(f) (equation 4)

Next, during preparation for calculating the cable insertion loss of cable #1, the calibrator (16) is connected to the input/output module (12) via ports P5 and P6. The test station (5) automatically checks whether the calibrator (16) is connected to P5-P6 using the automatic check circuit shown in FIG. 10 (step 1107).

If the calibrator (16) is connected, the insertion loss of cable #1 is determined (step 1108). The computer (15) switches the connection to establish a signal path through cable #1 and bypassing the amplifier a3, as highlighted by the "x" in fig. 13H. The VSG generates signals through the signal path according to the calibration signal script. The signal is received at the VSA and measured and temporarily stored. Fig. 13I illustrates calculation of the insertion loss value of cable #1 according to the following formula (step 1110):

IL_Cable#1(f)＝L_VSG(f)-L_VSA(f)-IL_p3-p1(f)--IL_p4-p6(f)-IL_23m(f)

(formula 6)

Wherein:

L_VSA(f) the method comprises the following steps A level (dB) of a signal received by the VSA;

IL_p3-p1(f) the method comprises the following steps Factory calibration of the insertion loss previously measured by the input/output module (12) from port P3 to P1;

: factory calibration of the insertion loss previously measured by the input/output module (12) from port P5 to P2;

IL_p4-p6(f) the method comprises the following steps Factory calibration (dB) of the insertion loss previously measured by the input/output module (12) from port P4 to P6;

IL_23m(f) the method comprises the following steps Combined insertion loss (dB) for cables #3 and # 2; see (formula 1)

Finally, the signal path conduction loss from port P3 through amplifier A3 to port P1 is determined (step 1109). The computer (15) switches the connection to establish a signal path that includes amplifier a3 and passes through cable #1, as highlighted by an "x" in fig. 13J. The VSG generates signals through the signal path according to the calibration signal script. The signal is received by the VSA, measured and temporarily stored. FIG. 13K illustrates the calculation of the conduction loss, IL, of the signal path from port P3 through amplifier A1 to port P1 according to the following equation_p3-p1wPA(f) (step 1110):

IL_p3-p1wPA(f)＝L_VSG(f)-L_VSA(f)--IL_p4-p6(f)-IL_23m(f)-IL_Cable#1(f)

(formula 7)

Wherein

: factory calibration (dB) of the previously measured insertion loss of the input/output module (12) from port P5 to P2;

IL_p4-p6(f) the method comprises the following steps Factory calibration (dB) of the previously measured insertion loss of the calibrator (16) from port P4 to P6;

IL_23m(f) the method comprises the following steps Cable with a protective layerCombined insertion loss (dB) for #3 and # 2; (see formula 1);

IL_Cable#1(f) the method comprises the following steps Insertion loss (dB) for cable # 1; (see formula 6).

In the example shown in fig. 13K, a negative insertion loss value indicates that there is actually an insertion gain rather than an insertion loss, which is about 28 dB.

It will be appreciated that the cable calibration procedure described above may be used to calibrate any cable, regardless of length, type or impairment. The cable calibration process is automated, quick and easy to perform because it is completely software driven and does not require manual handling of the cable. Furthermore, it will be appreciated that the cable calibration process need not be repeated. This is because the calibrator (16) and the cables are considered as part of the test bench (5) and do not need to be disconnected from the input/output module (12) at all, or at least as frequently as in conventional test benches.

Step D: the test station calibrates the DUTs for transmit and receive mode for combined conduction and wireless signal loss. The conduction signal loss of the test station (5) is calibrated when the DUT is in transmit mode and the DUT is in receive mode (FIG. 11B, steps 1111-. Typically, this calibration is accomplished by constructing appropriate partially conductive and partially wireless signal channels in sequence from the VSG through the VSA, using the VSG to generate signals of known power levels through these channels according to a calibration signal script, using the VSA to measure the signal power level at the end of the signal channel, and after accounting for other known power losses, calculating the difference between the signal power levels at the VSG and VSA. As described below, the calibrator (16) acts as a proxy for the DUT in transmit and receive modes.

During preparation for these calibrations, the connection between the calibrator (16) and the input/output module (14) is disconnected at P5-P6, and the calibrator (16) is placed on the scanner (10) as shown in FIG. 14A (step 1111). The computer (15) switches the connection to establish a signal path as highlighted by "x" in fig. 14A. The computer (15) loads the self-calibration data file, sets the VSG to transmission mode, and causes the VSG to generate random wireless data signals at maximum power and data rate on the appropriate channel, and the signals are sent by the calibrator (16) to the antenna probe array (101) of the scanner (10) and then transmitted to the VSA (step 1112). The scanner (10) locates the position of the calibrator (16) by interrogating each antenna probe (101) in the antenna array and selecting the one that receives a strong signal from the calibrator (step 1113). The scanner (10) can self-calibrate as needed during the process.

Conduction and wireless signal loss between the DUT and the VSA in the transmit mode are determined. The computer (15) switches the connection to the low gain signal path including amplifier a1 (but bypassing amplifier a2) as shown in fig. 14A. The VSG generates signals through the signal path according to the calibration signal script. The signal is wirelessly transmitted by the calibrator (16) to the antenna probe array (101) of the scanner (10) and then conducted to the VSA (step 1114). FIG. 14B illustrates the calculation of the combined conduction and radio loss, IL, from the calibrator antenna (160), through the amplifier A1 to the port RF1 through the emphasized signal path segment according to the following equation_TotwTX(f) (step 1116).

IL_TotwTX(f)＝L_{CaltbratorTX_EIRP}(f)+IL_{DUT_Ant_Dist}(d，f)-L_VSA(f)

(formula 9)

Wherein

L_{CalbratorTX_EIRP}(f) The method comprises the following steps An accurate calibration level (dB) of the signal emitted by the calibrator (16);

wherein

L_{CaltbratorTX_EIRF}(f)＝L_VSG(f)-IL_Cable#8(f)-IL_P3-P1wPA(f)-IL_Cable#1(f)-IL_{CaltbratorP4-EIRP}(f)(dB)

L_VSG(f) The method comprises the following steps A previously calculated signal (dB) emitted by the VSG;

IL_Cable#3(f) the method comprises the following steps Insertion loss (dB) measured at each test script frequency before cable #3 is referred to (equation 4) and (equation 5);

IL_P3-P1wPA(f) the method comprises the following steps From the amplified P3 to P1 channels, the insertion loss previously calculated by the input/output module (12); see (formula 7);

IL_Cable#1(f) the method comprises the following steps Insertion loss (dB) calculated before cable # 1; see (formula 6);

IL_{CaltbratorP4-EIFP}(f) the method comprises the following steps A previous insertion loss factory calibration (dB) of a calibrator (16) including an antenna (160);

IL_{DUT_Ant_Dist}(d, f): the previously calculated loss (dB) due to the DUT antenna being separated from the scanner (10) board as a function of separation d and frequency f;

L_VSA(f) the method comprises the following steps The level (dB) of the signal received by the VSA.

It can be noted from equation 9 that if the power level L is emitted from the calibrator (16)_{CaltbratorTX_EIRF}(f) And the power level L of the signal received at the VSA_VSA(f) Are all accurately known, then IL can be accurately estimated_TotwTX(f) Without the need to know exactly any losses in the receive path between the calibrator (16) and the VSA, provided that these losses are repeatable. This relaxes the requirements on any components in the receiving channel of the test bench (5).

Next, the computer (15) switches the connection to establish the high gain signal path shown in fig. 14A, but also includes amplifier a2 in series with amplifier a 1. The VSG generates signals through the signal path according to the calibration signal script. The signal is wirelessly transmitted by the calibrator (16) to the antenna probe array (101) of the scanner (10) and then conducted to the VSA (step 1115). FIG. 14C illustrates calculation of the conduction loss IL for a segment of the signal path from the scanner antenna (160) through amplifiers A1 and A2 to the port RF2 according to equation 9 above_TotwTX(f) (step 1116).

Next (not shown in fig. 11B), the conduction and wireless signal loss between the VSG to the DUT in receive mode is determined. The computer (15) switches the connection to establish "x" strong as in FIG. 14DThe signal path shown is modulated. The VSG generates a signal according to the calibration signal script. The signal is wirelessly transmitted by the antenna probe array (101) to the calibrator (16) and then conducted to the VSA. FIG. 14E illustrates the calculation of the combined conduction and wireless loss IL from the port RF2 to the section of the calibrator antenna (160) in the emphasized signal path according to the following equation_TotwRX(f) (step 1116):

IL_TotwRX(f)-L_VSG(f)+IL_{DUT_Ant_Dist}(d，f)-L_{CaltbratorRX_EIRP}(f) (formula 10A)

Wherein:

L_VSG(f) the method comprises the following steps A previously calibrated signal (dB) emitted by the VSG;

L_{CalibratorRX_EIRP}(f) the method comprises the following steps An accurately calculated level (dB) of the signal detected by the calibrator (16);

wherein:

L_{CalibratorRX_EIRP}(f)＝

L_VSA(f)+IL_Cable#2(f)+IL_P1-P2TX(f)+IL_Cable#1(f)+IL_{CaltbratorP4-EIRP}(f)in(dB)；

IL_Cable#2(f) The method comprises the following steps Insertion loss (dB) for cable # 2; see (formula 4) and (formula 5)

IL_P1-P2RX(f) The method comprises the following steps Insertion loss (dB) from port P1 to P2 in the input/output module (12) that has been previously factory calibrated;

IL_Cable#1(f) the method comprises the following steps Insertion loss (dB) of Cable #1, see (equation 6)

IL_{CaltbratorP4-EIRP}(f) The method comprises the following steps Calibrator(16) (including the antenna (160)) has a previously factory calibrated insertion loss (dB).

At the end of step D, the calibrator (16) is removed from the scanner (10) and reconnected to the input/output module (14) at ports P5-P6. The test bench (5) is fully calibrated and can be used for additional calibrations according to phases E, F and G, or can be used for DUTs according to phase H.

And a stage E: the test bench (5) is calibrated (optional) for temperature effects. It will be appreciated by those skilled in the art that certain components in the test station (5), such as the power amplifiers a1, a2, A3 shown in fig. 7, may behave differently with temperature. The accuracy of the test bench (5) can be further improved using a temperature calibration method to calibrate the test bench (5) for temperature effects.

The temperature calibration process may be performed at any time. In one embodiment, the temperature calibration process may be performed between successive DUT tests as the DUT just tested is just removed from the scanner (10) and another DUT is being placed onto the scanner (10). In this way, the temperature calibration process does not increase the overall time of the DUT test process.

The temperature calibration process can be performed at one signal frequency or several different signal frequencies. In one embodiment, the temperature recalibration process is performed at one signal frequency and applied identically to signals at all other frequencies, assuming that the effect of temperature changes is not a function of signal frequency. In another embodiment, a temperature recalibration process is performed for at least two different signal frequencies (e.g., 2.45GHz, 5GHz, 5.4GHz, and 5.8GHz) to establish a temperature recalibration line or curve, which can establish a trend line that extrapolates the effect of temperature on the signal frequencies to signal frequencies between these frequencies. In another embodiment, the temperature recalibration may be performed at multiple frequencies, for example, at each frequency of the signal encoded by the calibration signal script.

The temperature calibration process for calibrating the effect of temperature on amplifier a3 (shown in fig. 5) is schematically illustrated in fig. 6.The temperature sensor monitors the current temperature T and is compared by the computer (15) to the temperature Ti of the previous temperature calibration, which may be a factory calibrated temperature (step 601). If the difference between T and Ti exceeds a threshold T, the computer (15) will check whether the test stand (5) is busy with another process (step 602). If the test station (5) is not busy, the computer (15) will establish a signal path through amplifier A3, as highlighted by the "x" in FIG. 5. The VSG generates signals through the signal path according to the calibration signal script. The signal is routed through the scanner (10) and received by the computer (15) for measurement (step 603). Next, test module (14) establishes signal path CALC #3, excluding amplifier A3, as indicated by "y" in FIG. 5. The VSG generates signals through the signal path according to the calibration signal script. The signal is routed through the scanner (10) and received by the computer (15) for measurement (step 604) these measured signal levels are compared to predetermined or pre-calibrated signal values for the same frequency at a specified temperature (step 605). The computer (15) calculates the difference between the following two as a temperature calibration factor for the amplifier a 3: the measured power level of the signal conducted through the signal path including amplifier a 3; and the measured power level of signals conducted through signal paths not including amplifier a 3. The temperature calibration factor may be used to adjust the total wireless and conductive insertion loss IL when testing a DUT in a receive mode_TotwRX(f)。

Temperature calibration procedure to calibrate the effect of temperature on amplifiers a1 and a2 (shown in fig. 7) is schematically illustrated in fig. 8. Steps (801) and (802) are the same as steps (601) and (602) described above. The computer (15) establishes a signal path through amplifiers A3 and a1, as indicated by the "x" in fig. 7. The VSG generates signals through the signal path according to the calibration test script. The signal is received by the VSA and measured and temporarily stored (step 803). Next, the computer (15) establishes signal paths through amplifiers A3, A2, and A1, as indicated by "x" and "y" in FIG. 7. The VSG generates signals through the signal path according to the calibration test script. The signal is received by the VSA and measured and temporarily stored (step 804). These measured signal levels are predetermined for the same frequency at a given temperatureOr pre-calibrated signal values (step 805). The computer (15) calculates the temperature calibration factors for amplifiers A3 and a1 (in common), and A3, a1, and a2 (in common) as the difference between: a measured power level of a signal through a channel including a particular amplifier; and a measured power level of a signal passing through a channel that does not include the particular amplifier. These temperature calibration factors may be used to adjust the total wireless and conductive insertion loss, IL, when testing a DUT in transmit mode_TotwTX(f) (step 806).

And F: the test bench (5) is calibrated (optional) with GU. The test bench (5) was calibrated using GU (FIG. 11C: steps (1118) to (1123)).

The GU is placed on the surface of the scanner (10) and the GU antenna is aligned with the antenna position mark on the surface of the scanner (10), as shown in FIG. 15A (step 1118). The computer (15) initializes the GU; setting GU to transmission mode; and causing the GUs to transmit random data at the maximum power and data rate on the appropriate channels (step 1119). The scanner (10) locates the GU by interrogating each of the exploratory probes (101) in the antenna array and selecting one that receives a strong signal from the GU (step 1120). The software establishes a wireless link between the system (10) and the GU, sets the gain, and sets the RF switch to the RFI/O connector (step 1121).

Next, the system (5) is calibrated using GU in transmission mode. The computer (15) switches the connection to establish a signal path as highlighted by "x" in fig. 15B. The GU is licensed to transmit signals at various frequency modulations and data rates. The signal is detected by the scanner (10) and conducted to the VSA (step 1122). By ascertaining the level L of a signal supposed to be generated by GU_GUTX(f) Level L of signal measured with VSA_GUTX(f) The difference between can be calibrated by the previously calibrated conduction and radio losses IL between the calibrator antenna (160) and the VSA_TotwTX(f) Cancellation, calibration of the test bench may be verified (5) (step 1123):

L_GUTX(f)-L_VSA(f)＝IL_TotwTX(f) (formula 10B)

Next (drawing)11C) are used to calibrate the system (5) using the GU in receive mode. The computer (15) switches the connection to establish signal paths as highlighted by "x" and "y" in fig. 15C. The VSG generates a signal along a signal path indicated by "x". The signal is emitted by the antenna probe (101) and received by the GU. Level L of signal generated by confirming VSG_VSG(f) Reporting the level L of the received signal with GU_CURX(f) The difference between can be measured by the previously calibrated conduction and radio losses IL between the VSG and the calibrator antenna_TotwRX(f) Cancellation, calibration of the test bench can be verified (5):

L_VSG(f)-L_GURX(f)＝IL_TotwRW(f) (formula 11)

Stage G: the calibrator (16) is used as a GU simulator calibration test bench (5) (optional).

The test bench (5) is calibrated using the calibrator (16) to simulate the various standards GU in transmission mode (FIG. 11D: steps (1124) to (1134)). It will be appreciated by those skilled in the art that when the DUT fabrication process is stable, the transmission function testing of the DUT primarily involves verifying that the components of the DUT have all been properly solder assembled. However, when the manufacturing process is not stable (e.g., at a commissioning or early production stage), the DUT may be affected by other problems, such as software instability (DUT or test program or driver), location and orientation of components within the DUT, component missing or malfunctioning, quality or design issues of the DUT printed circuit board, and timing issues. The foregoing problems may result in one or more of the following signal parameters being out of specification: (a) a transmission level per frequency; (B) modulation and data rate; (C) correlation signal integrity as measured by an Error Vector Magnitude (EVM) parameter; (d) spectral mask and uniformity; (e) occupied Bandwidth (OBW); (f) phase noise and IQ imbalance; (g) a clock frequency offset; and (h) center frequency leakage. GUs of different standards may be simulated by preparing a calibration signal script encoding for transmitting signals having one or more target signal parameters that are out of specification to varying degrees. Table 1 lists, by way of non-limiting example, parameters TXout of a transmission signal of a DUT design rule_GU1And TXout_GU2For "good", "reluctant" and "bad" GU in transmission mode. By preparing a calibration signal script for the VSG to adjust the output level to match the target value of 12.5dBmEIRPresp.9.5dBmEIRP, and by releasing the EVM from the inherently high linearity of-35 dB to-14 dBresp. -26dB, the calibrator (16) can accurately simulate the DTU of DUTs and various standards. The signal file may be further modified to reduce OBW to degrade any subcarriers or to affect the spectral mask as desired.

To begin the calibration process, the calibrator (16) is placed on the scanner (10) (step 1124). The computer (16) reads the calibration signal script, sets the test module (14) to a transmission mode, and causes the calibrator (16) to transmit random data at maximum power and data rate on the appropriate channel (step 1125). The scanner (10) determines the position of the calibrator (16) by interrogating each antenna probe (101) in the antenna array and selecting a single probe that receives a strong signal from the calibrator (step 1126). The system (5) adjusts the gain setting of the scanner input/output module (12) according to the gain setting read from the wireless coupling loss file (step 1128) or by calculating the gain setting based on previous wireless values (step 1129).

The computer (15) switches the connection to establish a signal path as shown with emphasis "x" in fig. 14A (step 1130). The VSG generates signals through the signal channel so that the signal at the calibrator antenna (160) has parameters specified by the calibration signal scripts for the DUT and the various levels GU (steps 1131, 1132, and 1133). In each case, the level L of the signal generated by the calibrator antenna (160) is ascertained_C(f) Level L of signal measured with VSA_VSA(f) Whether the difference between can be measured by the previously calibrated conduction and radio losses IL between the calibrator antenna (160) and the VSA_TotwTX(f) Cancellation to verify calibration of the test bench (5) (step 1134):

L_C(f)-L_VSA(f)＝IL_TotwTX(f) (formula 12)

It will be appreciated that the above relationships each calibrate the test rig (5) by detecting a correlation between the target signal level at the calibrator antenna (160) and the measured signal level at the VSA, and verify the performance of the scanner (10). The calibration results may be stored as calibration verification values and displayed to the user in the form of a report.

In the illustrated embodiment of the test bench (5), the calibrator (16) is used to simulate a SISO (i.e. 1 receiver, 1 transmitter) GU. In other embodiments (not shown), the calibrator (16) may be used to simulate MIMO (i.e., at least one receiver and more than one transmitter, or more than one receiver and at least one transmitter) GU devices by equipping the test station (5) with VSG units having bi-directional amplifiers, calibrator antennas (160), and scanners (10) having wireless coupling boards with more than one simultaneous coupling channels.

The test station (5) is also calibrated using a calibrator (16) to simulate GUs of various different standards in receive mode. For a DUT in receive mode, it is conventional to determine its receive sensitivity at a given channel frequency, data rate, and receive power level by counting the number of data packets and calculating the Bit Error Rate (BER). For 802.11a/g/n modulation, the received power minimum sensitivity is defined as the power level at which the BER reaches 10% of a frame comprising 4096-bit PSDU (physical layer service data unit). For 802.11b, receive power least sensitivity is defined as the power level at which the BER reaches 8% of a frame comprising 4096 bits PSDU (physical layer service data unit). GUs of different standards can be simulated by preparing a calibration signal script encoding for a received signal having a specified BER and received power level pair.

Table 2 summarizes, by way of non-limiting example, the target received power levels and target BERs corresponding to the DUT design specifications and for "good", "marginal" and "bad" GU in receive mode.

It will be appreciated that since the test signal is generated by the VSG under the control of the calibration signal script, one or more other signal parameters may be compromised to more realistically simulate the real conditions under which the DUT needs to operate to reach the target BER. For example, and without limitation, the signal generated by the VSG may be slightly attenuated, from-35 dB EVM to-15 dB EVM.

In order for the calibrator (16) to emulate GU in receive mode, the test bench (5) must further comprise BER measuring means to measure the BER of the signal received by the calibrator (16). In one embodiment, the BER measuring device includes a receiver (e.g., without limitation, a WLAN receiver) and a BER table for counting BER. Although possible, this embodiment is not preferred because it is extremely complex and because chipset specific (chipmetspecific) and minimum receive sensitivity performance may vary with time and temperature. In an alternative embodiment, the test bench (5) is equipped with: BER measuring means to measure BER at the VSA; analyzer signal amplitude varying means for varying the amplitude of the signal received at the VSA; and generator signal amplitude changing means for changing the amplitude of the signal generated by the VSG. The BER measuring means, the analyzer signal amplitude varying means and the generator signal amplitude varying means may be embodied as hardware, software, or both. In an embodiment, both the BER measuring means and the analyzer signal amplitude varying means may be implemented entirely in software. For example, variably controllable input attenuators may be used with VSAs (e.g., in the LitePointIQ 2010)^TMOn a tester (LitePoint, ca, usa)) to change the input receive level and set it at the target receive power level, thereby increasing or decreasing the BER. The input reception level of the VSA may be different from the actual device, but the BER conditions are similar. It is also possible to extract the baseband signal from the back of the instrument and calculate the BER without adding or changing the main hardware or software. Or, when the power level is at most the VSAWhen the small received power is sufficiently high, the signal can be improved so there will be a certain BER at the VSA regardless of the power level.

To begin the calibration process, the computer (15) switches the connection to establish a signal path as shown with emphasis "x" in fig. 14D. The VSG generates signals through the signal path according to the calibration signal script. The analyzer signal amplitude varying means is used to attenuate (or amplify) the signal at the VSA until the power level of the signal matches the target input reception level. The generator signal amplitude changing means is used to attenuate (or amplify) the signal at the VSG until the BER of the signal measured by the BER measuring means matches the target BER. The power level of the signal generated at the VSG required to establish the target BER for the VSA is recorded and related to the target input receive level and the target BER.

Stage H: and testing the DUT. Once the test bench (5) has been satisfactorily calibrated, it can be used to test DUTs. One embodiment of the testing process is shown in FIG. 2. The DUT (in this case a wlan DUT) is manually placed on the surface of the scanner (10) so that the DUT antenna can transmit signals to and from the antenna probe array (101) (step 201). A template layout for different DUTs is drawn on the surface of the scanner (10) to facilitate proper placement of the DUTs. No physical connection is made between the test station (5) and the DUT. Bidirectional communication to and from the DUT is achieved by a wireless protocol. Optionally, the DUT may be connected by power or digital connection lines to provide a power supply and/or to enable bi-directional communication. Bidirectional communication in wireless or wired mode refers to initialization, starting of a test, reading of results, etc. The DUT or the test stand (5) itself may be preliminarily inspected. The DUT is ensured to be connected to the power supply and any shielding boxes (11) have been shut down (step 202). The DUT is initialized in the transmit mode and requires random data to be transmitted at maximum power and data rate on the appropriate signal (step 203). The scanner (10) interrogates each antenna probe (101) in the antenna array and selects one probe that receives a strong signal from the DUT (step 204). If the antenna probe array (101) is unable to detect the DUT, the guard box is opened, ensuring that the DUT is in the proper position in the antenna probe array (101) (step 205). Conversely, if the antenna probe array (101) is capable of detecting a DUT, the scanner (10) establishes a wireless link to the DUT; the test bench (5) sets a gain level; reading calibration files for the test bench (5) and the DUT type; calibration is performed if necessary; setting the RF switch to the RFI/O controller; the concurrent signal indicates that the scanner (10) is ready for a continuous inspection task (step 206). Standard WLAN detection may then be performed, wherein the test module (14) adds a calibration factor to the set calibration; the DUT transmit functions are calibrated against the DUT chipset and various transmit and receive rates are detected (step 207). If the DUT fails the test, the test may be repeated according to steps 203 through 207 (channel 208), or the DUT may be removed from the guard box, scanned for identity and assigned to a "bad" device box (step 209). If the DUT passes the test, the DUT is removed from the guard box, scanned for identity, and then allocated into a "good" equipment box (step 210).

Switching from one DUT to another of a different type can be achieved by switching test software in the test computer (15). Such a test station (5) may cover conventional testing and calibration of most single-input single-output (SISO) WiFi and bluetooth devices. In one embodiment, any DUT having a high transmitter or a weak transmitter may be tested, from +34dBmEIRP to-22 dBmEIRP (2.4-2.5GHz band, either WiFi or Bluetooth), and +28dBmEIRP to-13 dBmEIRP (5-6GHz band, 802.11 a/n).

It will be apparent to those skilled in the art that various modifications, changes, and variations can be made to the foregoing disclosure without departing from the scope of the invention as defined in the following claims.

Claims

1. A test station for testing a wireless device in a transmit mode, the test station comprising:

a. a signal generator for generating a conducted calibration signal;

b. a calibrator including at least one calibrator antenna conductively coupled to the signal generator for wireless transmission of the calibration signal;

c. a wireless scanner comprising at least one receiving antenna for wirelessly receiving the calibration signal;

d. a signal analyzer conductively coupled to the receive antenna to receive and measure a power level of the calibration signal; and

e. a computer, comprising:

i. a memory for storing a calibration signal file encoding for a target transmission power level of the calibration signal at the calibrator antenna, and a set of program instructions implementing a method comprising the steps of:

providing a signal path comprising a conductive path from the signal generator to the calibrator antenna, a wireless path from the calibrator antenna to the receive antenna, and a conductive path from the receive antenna to the signal analyzer;

providing a calibration signal script encoding for a calibration signal having a target transmission power level at the calibrator antenna;

generating the calibration signal through the signal channel using the signal generator;

measuring a power level of the calibration signal using the signal analyzer; and

correlating the target transmission power level of the calibration signal with a measured power level of the calibration signal.

ii. A processor operatively connected to the memory, the signal generator, and the signal analyzer, the processor configured to execute the set of program instructions.

2. A test bench according to claim 1, wherein said calibrator may be selectively positioned on or separate from said wireless scanner.

3. A test bench according to claim 1, wherein said calibrator further comprises a housing for protecting said calibrator antenna.

4. The test bench of claim 1, wherein said calibrator antenna is conductively connected with said signal generator via a calibrator signal channel comprising:

a. a port selectively conductively connectable with the signal analyzer;

b. a calibrator antenna switch for selectively connecting the calibrator antenna to the calibrator signal path and disconnecting the port from the calibrator signal path or disconnecting the calibrator antenna from the calibrator signal path and connecting the port to the calibrator signal path.

5. A test bench according to claim 4, wherein said calibrator antenna switch is operatively connected to said computer.

6. The test stand of claim 1, wherein the wireless scanner comprises a near field scanner.

7. A test bench according to claim 1, wherein said memory storing said calibration signal file is modifiable.

8. A method of calibrating a test station for testing a wireless device in a receive mode, the test station comprising a wireless scanner, a calibrator having a calibrator antenna, a signal generator, and a signal analyzer, the wireless scanner comprising a transmit antenna, the method comprising the steps of:

a. providing a signal path comprising a conductive path from the generator to the transmit antenna; a wireless channel from the transmit antenna to the calibrator antenna; and a conductive path from the calibrator antenna to the signal analyzer;

b. providing calibration signal script encoding for a calibration signal having a target received power level and a corresponding target BER at the signal analyzer;

c. generating the calibration signal through the signal channel using the signal generator;

d. setting a power level of the calibration signal received at the signal analyzer to the target received power level;

e. measuring a BER of the calibration signal received at the signal analyzer;

f. changing, if necessary, the power level of the calibration signal generated by the signal generator to converge the measured BER toward the target BER; and

g. correlating the target received power level and the target BER to a power level of the calibration signal generated by the signal generator, wherein the BER measured at the signal generator converges towards the target BER.

9. The method of claim 8, wherein the calibration signal script additionally specifies one or more of the following signal parameters of the calibration signal: frequency, modulation, and data rate; error vector magnitude, spectral mask and uniformity; occupied bandwidth; phase noise; I-Q imbalance; a clock frequency offset; a center frequency leak; or time sequence.

10. A test station for testing a wireless device in a receive mode, the test station comprising:

a. a signal generator for generating a conducted calibration signal;

b. the wireless scanner comprises at least one transmitting antenna, and the transmitting antenna is in conductive connection with the signal generator so as to wirelessly transmit the calibration signal;

c. a calibrator comprising at least one calibrator antenna for wirelessly receiving the calibration signal;

d. a signal analyzer conductively coupled to the calibrator antenna to receive and measure a power level of the calibration signal;

e. generator signal amplitude varying means operatively connected to the signal generator for varying the amplitude of the calibration signal generated by the signal generator;

f. analyzer signal amplitude varying means operatively connected to said signal analyzer for setting the amplitude of said calibration signal received by said signal analyzer;

g. a BER measuring device operatively connected to the signal analyzer to measure a BER of the calibration signal received by the signal analyzer; and

h. a computer, comprising:

i. a memory for storing a calibration signal file encoding a target received power level and a corresponding target BER for the calibration signal at the signal analyzer, and a set of program instructions implementing the method of claim 8;

ii. A processor operatively connected to the memory, the signal generator, the signal analyzer, the generator signal amplitude altering device, the analyzer signal amplitude altering device, and the BER measuring device, the processor configured to execute the set of program instructions.

11. A test bench according to claim 10, wherein said calibrator may be selectively positioned on or separate from said wireless scanner.

12. A test bench according to claim 10, wherein said calibrator further comprises a housing for protecting said calibrator antenna.

13. A test bench according to claim 10, wherein a memory storing said calibration signal files is modifiable.