KR102591192B1 - Rf system with signal calibration feedback circuit and algorithm for system performance stabilization and method of operation thereof - Google Patents

Abstract

An RF system and its operation method using a signal compensation feedback circuit and algorithm for stabilizing system performance are presented. An RF (Radio Frequency) system to which a signal compensation feedback circuit and algorithm for stabilizing system performance according to an embodiment of the present invention is applied, performs signal size and phase correction for the amount of change in system performance over time in the RF system. It may include a feedback circuit including an RF switch and a directional coupler configured in at least one of the transmitter system and the receiver system.

Description

RF system with signal compensation feedback circuit and algorithm for stabilizing system performance and its operation method {RF SYSTEM WITH SIGNAL CALIBRATION FEEDBACK CIRCUIT AND ALGORITHM FOR SYSTEM PERFORMANCE STABILIZATION AND METHOD OF OPERATION THEREOF}

The embodiments of the present invention below relate to communication devices and radar systems over the millimeter wave band, and more specifically to RF (Radio Frequency) systems that can reduce system performance errors using signal calibration techniques. It relates to systems and their operating methods.

Recently, as the number of 5th generation or higher mobile communication devices has increased, interest in higher frequency bands than the previously used RF frequency band is increasing. One of them is the millimeter wave band, and research on antenna technology that utilizes millimeter wave characteristics is actively underway.

Compared to 4th generation or lower mobile communication devices, signals in the millimeter wave band have a short wavelength, resulting in high transmission loss, and high thermal noise due to the relatively wide bandwidth is the main cause affecting the millimeter wave system. In systems in the millimeter wave band, large errors in system performance can occur due to temperature and surrounding environment, and to reduce this, signal compensation techniques become more important as the frequency band increases.

The low frequency band previously used operated the system and stabilized the performance of the system through preheating. Preheating saturates the internal temperature of the system and keeps the characteristics of the device whose performance is affected by temperature constant.

However, in the millimeter wave band, the wavelength is shorter than in the low frequency band, so the sensitivity to changes in system performance to temperature is high. Because of this, there is a large change in the size and phase of the signal even after preheating of the system, so there are limits to signal compensation using existing methods.

Therefore, in systems above the millimeter wave band, a new signal compensation technique is required to achieve stable performance.

Korean Patent No. 10-2251449 describes technology related to a radio frequency (RF) transmitter and noise mitigation device.

Korean Patent No. 10-2251449

Embodiments of the present invention describe an RF system and its operating method using a signal compensation feedback circuit and algorithm for stabilizing system performance, and more specifically, implement more accurate and stable RF system performance using a new signal compensation technique. And based on this, we provide technology to increase the accuracy of implementing communication and radar technology in the millimeter wave band.

Embodiments of the present invention form a conventionally used RF transmitter and receiver system as is, while additionally implementing a compensation circuit to apply compensation values to the gain and phase of the internal elements of the system, thereby eliminating system errors and increasing performance stability. The aim is to provide an RF system and its operation method using a signal compensation feedback circuit and algorithm to stabilize system performance.

An RF (Radio Frequency) system to which a signal compensation feedback circuit and algorithm for stabilizing system performance according to an embodiment of the present invention is applied, performs signal size and phase correction for the amount of change in system performance over time in the RF system. It may include a feedback circuit including an RF switch and a directional coupler configured in at least one of the transmitter system and the receiver system.

The feedback circuit measures the performance change in size and phase of the system signal and then applies a gain compensation algorithm to convert the signal in real time from a digital DAC (Digital to Analog Converter) or ADC (Analog to Digital Converter). Compensation for size and phase can be made.

The feedback circuit can be implemented from the output of the mixer to the active element at the very end to measure the amount of performance change in the size and phase of the signal of the system.

The feedback circuit is implemented from the output of the mixer to the active element at the very end, and by implementing the feedback circuit in each of the active elements, the signal can be compensated by checking the amount of performance change for the size and phase of each signal. there is.

The transmitter system includes an IF signal generating DAC for signal compensation inside the transmitter system, and the DAC is capable of compensating the signal in real time by the amount of change in system performance measured using digital signal processing technology.

The receiver system includes an IF signal reception ADC for signal compensation, and the ADC is capable of compensating signals in real time by the amount of change in system performance measured using digital signal processing technology.

The feedback circuit includes an RF switch, a frequency down-converting mixer, and a gain/phase detector, and the RF switch and the directional coupler are installed in the input/output portion of the amplifier to feedback an output signal when the same signal is applied to the amplifier. As a result, the characteristics of the module can be measured.

The feedback circuit may obtain a change in performance of the amplifier, which is an active element, by comparing signals of the RF path before passing through the amplifier and the RF path after passing through the amplifier.

A method of operating an RF (Radio Frequency) system using a signal compensation feedback circuit and algorithm for stabilizing system performance according to another embodiment of the present invention involves correcting signal size and phase for the amount of change in system performance over time in the RF system. It may include performing signal compensation using a feedback circuit including an RF switch and a directional coupler configured in at least one of the transmitter system and the receiver system.

Performing signal compensation using the feedback circuit includes transmitting and receiving an RF signal in an RF system to obtain a reference gain; Obtaining signal characteristics before passing through an amplifier among active elements within the system; Obtaining signal characteristics after passing through the amplifier; After obtaining the reference gain, transmitting and receiving an RF signal to which a compensation technique using a feedback circuit is applied; Obtaining signal characteristics before passing through an amplifier among active elements within the system, acquiring signal characteristics after passing through the amplifier, and measuring performance changes in size and phase of the signal of the system; and applying the measured change in performance to a gain compensation algorithm of the system to compensate for the magnitude and phase of the signal in real time.

The step of performing signal compensation using the feedback circuit is to measure the amount of performance change in the size and phase of the signal of the system and then apply a gain compensation algorithm to use a digital to analog converter (DAC) or analog converter (ADC). to Digital Converter) can compensate for the size and phase of the signal in real time.

In the step of performing signal compensation using the feedback circuit, the amount of performance change in the size and phase of the signal of the system can be measured by implementing the feedback circuit from the output of the mixer to the active element at the extreme end.

In the step of performing signal compensation using the feedback circuit, the feedback circuit is implemented from the output of the mixer to the active element at the extreme end, and the feedback circuit is implemented in each of the active elements to determine the size and size of each signal. The signal can be compensated by checking the performance change in phase.

The step of performing signal compensation using the feedback circuit includes a DAC generating an IF signal for signal compensation inside the transmitter system, wherein the DAC signals in real time as much as the performance change of the system measured using digital signal processing technology. can compensate.

The step of performing signal compensation using the feedback circuit includes an IF signal receiving ADC for signal compensation inside the receiver system, wherein the ADC performs real-time data by the amount of change in performance of the system measured using digital signal processing technology. The signal can be compensated.

According to embodiments of the present invention, the amount of change in active elements can be measured in real time even in a millimeter wave band system where the performance change depending on temperature is large.

According to embodiments of the present invention, a high-frequency band system is implemented at low cost by converting the frequency band of the signal to measure and compensate for the change in performance of the high-frequency band in the low-frequency band. The higher the frequency band, the more expensive the equipment, and the higher the frequency, the more expensive the system is. It is sensitive and can solve problems that have realistic limitations where performance can easily change.

According to embodiments of the present invention, it is possible to measure not only the amount of change in the entire system but also the amount of change in signal characteristics of elements or modules within the system, and compensate for the value according to the amount of performance change.

According to embodiments of the present invention, it is possible to measure the amount of change in signal characteristics of internal elements or modules in the entire system, thereby identifying the elements that are most or least sensitive to the influence of the surrounding environment.

According to embodiments of the present invention, signal synchronization can be implemented in a multi-channel system by applying a signal compensation technique to the imbalance phenomenon of signal characteristics that can occur even in the same system.

Figure 1 schematically shows the structure of a transmission system using a direct frequency conversion method according to an embodiment of the present invention.
Figure 2 schematically shows the structure of a reception system using a direct frequency conversion method according to an embodiment of the present invention.
Figure 3 schematically shows the structure of a transmission system for direct frequency conversion that includes a feedback circuit for applying a compensation technique according to an embodiment of the present invention.
Figure 4 shows an example of the order of transmitting and receiving RF signals and applying compensation techniques according to an embodiment of the present invention.
Figure 5 shows the RF signal path of a transmission system for direct frequency conversion for measuring the amount of change in the system through a feedback circuit according to an embodiment of the present invention.
Figure 6 schematically shows the structure of a receiving system for direct frequency conversion that includes a feedback circuit for applying a compensation technique according to an embodiment of the present invention.
Figure 7 shows the RF signal path of a receiving system for direct frequency conversion to measure the amount of change in the system through a feedback circuit according to an embodiment of the present invention.
Figure 8 schematically shows a gain/phase detector for comparing and analyzing data of a signal obtained through a feedback circuit according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the described embodiments may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, various embodiments are provided to more completely explain the present invention to those with average knowledge in the art. The shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

Depending on the characteristics of the internal elements and modules of mobile communication devices, the amount of change in signal characteristics depending on the environment may vary for each device. The more active elements there are and the higher the frequency, the more sensitive system performance can be to all experimental environments, including temperature. In addition, system performance may be affected by the structure of the module's heat sink and housing, which allows heat to escape easily.

However, depending on the characteristics and structure of every system, establishing a compensation technique environment requires a large investment in time and money. One way to solve this problem is to monitor and compensate for the signal change in the entire system in real time. Here, the amount of signal change in the entire system can be measured by comparing the signal before and after passing through the active element based on the active element.

According to the Nyquist theorem, the characteristics of the signal before and after passing through the active element in the millimeter wave band can be analyzed only if the number of samples is twice as high as the frequency of the RF signal. However, direct comparison between millimeter wave signals is difficult due to technical limitations.

As a way to solve this problem, a mixer can be used according to embodiments of the present invention. If the frequency of an RF (Radio Frequency) signal is converted through a mixer, the size and phase of the IF (Intermediate Frequency) signal can be analyzed due to its relatively low frequency. At this time, if the frequencies are not the same, errors may occur in the phase change, so the frequencies must be made the same using the same LO (Local Oscillator) signal.

Through the above method, the millimeter wave band system can measure the characteristics of the signal before and after passing the active element by utilizing the system structure for direct frequency conversion, and by comparing the characteristics of the two measured signals, the active element can be measured over time. It is possible to calculate how much the size and phase of the signal have changed after passing. Afterwards, stable system performance can be derived by compensating the input and output signals of the system by the amount of change in the system.

The change in signal characteristics of the RF system or its internal modules or elements can be measured. In this case, an RF switch, RF directional coupler, etc. are required. For example, in the case of a transmitter for direct frequency conversion, the PA (Power Amplifier) uses the most current and generates a lot of heat. By installing an RF switch or directional coupler in the input/output part of the PA device, the characteristics of the module can be measured by feeding back the output signal when the same signal is applied to the PA device. In addition, in the case of a receiver for direct frequency conversion, the amount of change in signal characteristics of the receiver system can be confirmed by implementing a feedback signal centered on an active element, LNA (Low Noise Amplifier).

A method of measuring changes in the characteristics of a signal can be done through a magnitude comparator and a phase comparator that can measure the magnitude and phase of the signal. By comparing feedback signals before and after passage of the active element, it is possible to measure the amount of change in the system over time. Here, the amount of change in the system is measured in real time through a compensation circuit after driving the system, and can be calculated through comparison between feedback signals. The RF signal characteristics can be compensated by directly controlling the characteristics of the IF signal of the frequency change system by the calculated change amount.

Embodiments of the present invention relate to a system that can reduce RF system performance errors using signal compensation techniques. The wavelength of the millimeter wave band is approximately 1 cm, and as the frequency increases, the wavelength becomes shorter. As the wavelength gets shorter, external factors such as heat can cause greater signal fluctuation. For this reason, signal compensation techniques are essential for systems above the millimeter wave band to maintain performance.

Embodiments of the present invention proposed a system structure to compensate for system performance by adding a feedback circuit to the RF system. By detecting and monitoring the performance of the RF system in real time through a feedback circuit, the amount of change in performance can be extracted by applying a signal compensation technique to the detected data. The performance error of the system can be improved by compensating the signal with digital signal processing technology to the extent of the extracted performance change.

An RF (Radio Frequency) system to which a signal compensation feedback circuit and algorithm for stabilizing system performance according to an embodiment of the present invention is applied, performs signal size and phase correction for the amount of change in system performance over time in the RF system. It may include a feedback circuit including an RF switch and a directional coupler configured in at least one of the transmitter system and the receiver system.

The feedback circuit measures the performance change in the size and phase of the system signal and then applies a gain compensation algorithm to determine the size and phase of the signal in real time using a digital DAC (Digital to Analog Converter) or ADC (Analog to Digital Converter). You can compensate for your status.

At this time, the amount of change in performance of the entire system or each element can be measured depending on the location of the feedback circuit. For example, the feedback circuit can be implemented from the output of the mixer to the active element at the very end to measure the amount of performance change in the size and phase of the signal of the system. As another example, the feedback circuit is implemented from the output of the mixer to the active element at the very end, and by implementing a feedback circuit in each active element, the signal can be compensated by checking the amount of performance change for the size and phase of each signal. .

At this time, an IF signal generating DAC for signal compensation may be included inside the transmitter system. DAC is a digital signal processing technology that can compensate for signals in real time by the amount of change in system performance measured. Additionally, the receiver system may include an IF signal reception ADC for signal compensation. ADC is a digital signal processing technology that can compensate for signals in real time by the amount of change in system performance measured.

The feedback circuit may include an RF switch, a frequency down-converting mixer, and a gain/phase detector, and an RF switch and a directional coupler are installed in the input/output portion of the amplifier to feed back the output signal when the same signal is applied to the amplifier. characteristics can be measured. At this time, the feedback circuit can obtain the amount of change in performance of the amplifier, which is an active element, by comparing the signal of the RF path before passing through the amplifier and the RF path after passing through the amplifier.

A method of operating an RF system using a signal compensation feedback circuit and algorithm for stabilizing system performance according to another embodiment of the present invention is to perform signal size and phase correction for the amount of change in system performance over time in the RF system. It may include performing signal compensation using a feedback circuit including an RF switch and a directional coupler configured in at least one of the transmitter system and the receiver system.

The steps of performing signal compensation using a feedback circuit include transmitting and receiving RF signals in the RF system to obtain a reference gain, acquiring signal characteristics before passing through the amplifier among the active elements inside the system, and acquiring subsequent signal characteristics; After obtaining the reference gain, a step of transmitting and receiving an RF signal to which a compensation technique using a feedback circuit is applied, acquiring signal characteristics before passing through the amplifier among the active elements inside the system, and acquiring signal characteristics after passing through the amplifier, It may include measuring the performance change in the size and phase of the signal, and applying the measured performance change to the system's gain compensation algorithm to compensate for the signal size and phase in real time.

As the mobile communication and radar markets above the millimeter wave band develop, demand for RF systems is rapidly increasing. Among them, as technology using array antennas develops, signal control technology between RF systems becomes essential. The proposed system structure not only maintains system performance, but also enables signal control through compensation techniques, making it applicable to various fields.

Below, an RF system and its operating method to which a signal compensation feedback circuit and algorithm for stabilizing system performance according to an embodiment of the present invention are applied will be described in more detail.

Figure 1 schematically shows the structure of a transmission system using a direct frequency conversion method according to an embodiment of the present invention.

As shown in FIG. 1, in order to generate a signal over the millimeter wave band, the signal can be transmitted through a direct frequency conversion structure using the mixer 102. Here, a direct frequency conversion structure capable of signal transmission can be expressed as a transmission system 100.

The transmission system 100 includes a digital to analog converter (DAC) 101 for generating IF signals, a mixer 102, and an oscillator 103 for local oscillator (LO) signals. Due to the non-linear characteristics of the output signal of the mixer 102, a spurious signal is generated in addition to the desired frequency signal. At this time, an RF band pass filter 104 can be used to propagate only the desired signal. Additionally, an isolator 105 may be further included to prevent oscillation of signals that are not removed by the RF band pass filter 104. The transmission system 100 transmits signals using a Power Amplifier (PA) 106 for final output.

Figure 2 schematically shows the structure of a reception system using a direct frequency conversion method according to an embodiment of the present invention.

As shown in FIG. 2, in order to receive signals over the millimeter wave band, a direct frequency conversion structure using the mixer 202 can be used. Here, a direct frequency conversion structure capable of receiving signals can be expressed as a receiving system 200.

Specifically, the receiving system 200 includes an Analog to Digital Converter (ADC) 201 for analyzing signals, a frequency down-converting mixer 202, and a Local Oscillator (LO) for use in the mixer 202. ) Includes an oscillator 203 for signals. At this time, if the power of the received RF signal is low, the SNR may deteriorate while passing through the receiving system 200, making signal analysis difficult. To prevent this, an LNA (Low Noise Amplifier) 207 is required, and an RF band pass filter 205 and an isolator 206 are installed to prevent signal oscillation and transmit only the desired signal. may be included. Additionally, an IF band pass filter 204 may be added to prevent spurious signals due to the non-linear characteristics of the mixer 202.

Figure 3 schematically shows the structure of a transmission system for direct frequency conversion that includes a feedback circuit for applying a compensation technique according to an embodiment of the present invention.

Referring to FIG. 3, the transmission system 300 for direct frequency conversion including a feedback circuit for applying a compensation technique according to an embodiment of the present invention is the transmission system 300 using the direct frequency conversion method described in FIG. A feedback circuit was added to detect changes in the characteristics of the internal elements of the system.

In order to transmit an RF signal, an IF signal is generated in the DAC (301) through a PC (313) for signal control and analysis. The generated IF signal is divided by the directional coupler 302 and transmitted to the frequency up-converting mixer 303 and the gain/phase detector 312, respectively. At this time, the signal transmitted to the frequency up-converting mixer 303 is used for millimeter wave signal transmission, and the signal transmitted to the gain/phase detector 312 is used as a reference signal for signal comparison. .

The LO signal input to the frequency up-converting mixer 303 can use the LO signal oscillator 304. The output signal of the frequency up-converting mixer 303 passes through the band pass filter 305 to remove spurious signals, and is connected to the RF switch 306 after the band pass filter 305. ) can be located. The RF switch 306 can control the RF path to implement the transmission system 300 for direct frequency conversion for analyzing changes in system performance or transmitting millimeter wave signals. For millimeter wave signal transmission, the signal output from the RF switch 306 passes through the isolator 307 and PA 308. The directional coupler 309 after the output terminal of the PA (308) can be used for transmitting millimeter wave signals and analyzing the amount of signal change after passing through the PA (308).

Here, the feedback circuit includes an RF switch 310, a frequency down-converting mixer 311, and a gain/phase detector 312. It is also possible to use an RF switch instead of the directional coupler 309, which may vary depending on the PA 308 output power.

Meanwhile, the gain/phase detector 312 will be described in detail with reference to FIG. 8 below.

Additionally, Path1 shown in FIG. 3 is an RF path for millimeter wave signal transmission. The order of the RF path is explained in more detail with reference to FIG. 4.

Figure 4 shows an example of the order of transmitting and receiving RF signals and applying compensation techniques according to an embodiment of the present invention.

Referring to FIG. 4, the transmission system for direct frequency conversion according to an embodiment of the present invention is used to transmit and receive RF signals, and inserts a compensation technique sequence between transmitting and receiving signals to improve system performance through a feedback circuit. Make compensation possible.

First, the transmission system for direct frequency conversion transmits and receives RF signals through Path1 (401). Next, among the active elements inside the system, the signal characteristics before passing through the amplifier are obtained through Path2 (402) before passing through the amplifier. Next, the signal characteristics after passing through the amplifier are obtained through Path3 (403). Meanwhile, the order of Path1 (401), Path2 (402), and Path3 (403) may change depending on the application field of the system, and the time required for each may also change. The path order (400) of the RF signal to obtain the reference gain of the system can be obtained immediately after operating the system.

In this example, after the RF signal path 400 to obtain the reference gain, the system performance analysis and compensation technique sequence 404 is implemented periodically. After Path3 (403), RF signal transmission and reception (405) using a compensation technique is again performed through Path1. After Path1 (405), the performance change value of the system can be calculated through Path2 (406) and Path3 (407) and this value can be applied to the system's gain compensation algorithm (408).

Meanwhile, Path1, Path2, and Path3 according to the transmission and reception system are shown in Figures 3, 5 to 7, respectively.

Figure 5 shows the RF signal path of a transmission system for direct frequency conversion for measuring the amount of change in the system through a feedback circuit according to an embodiment of the present invention.

Referring to FIG. 5, it shows the RF signal path of the transmission system 500 for direct frequency conversion for measuring the amount of change in the system through a feedback circuit according to an embodiment of the present invention, and is a feedback circuit for applying a compensation technique. The structure of the transmission system for direct frequency conversion included is the same as in FIG. 3. As shown in FIG. 5, Path2 (402) and Path3 (403) in FIG. 4 are shown as an example to analyze characteristics before and after passing through the amplifier 508.

Path2 and Path3 shown in FIG. 5 are configured based on the PA 508 that has the greatest impact on the performance of the transmission system 500.

Path2 is the RF path before passing through the PA (508), including the DAC (501), the directional coupler (502), the frequency up-converting mixer (503), the band pass filter (505), the first RF switch (506), and the first RF switch (506). 2 RF switch 510, frequency down-converting mixer 511, and gain/phase detector 512. At this time, the order of each element may change depending on the embodiment.

Path3 is the RF path after passing through the PA (508), DAC (501), directional coupler (502), frequency up-converting mixer (503), band pass filter (505), first RF switch (506), and isolator. The order is 507, PA 508, directional coupler 509, second RF switch 510, frequency down-converting mixer 511, and gain/phase detector 512.

Path3 differs from Path2 in the isolator 507, PA (508), and directional coupler 509. Except for PA (508), the remaining elements are passive elements and the amount of signal change is kept constant. In other words, the performance of the signal passing through the passive element does not change over time. Therefore, by comparing the signals passing through Path2 and Path3, the change in performance of the active element PA (508) can be obtained.

The compensation technique according to an embodiment of the present invention can obtain system characteristic information through Path2 and Path3. System characteristic information can be obtained through the gain/phase detector 512, and the input signal of the gain/phase detector 512 is the IF reference signal transmitted from the directional coupler 502 and the signal passing through Path2 and Path3. Here, the IF reference signal is It can be expressed as, and can be expressed as the following equation.

[Equation 1]

here, are the magnitude and phase of the signal after the IF signal generated in the DAC 501 passes through the directional coupler 502.

Second, the signal passing through Path2 and Path3 respectively is It can be expressed as, and can be expressed as the following equation.

[Equation 2]

here, class are the magnitude and phase of the signal after passing through Path2 and Path3, respectively. In the gain/phase detector 512 via and The power difference ( )and and The power difference ( ) can be calculated.

The first measured value after operating the system and The difference value is the reference gain ( ) can be set. and The difference includes gain information of the PA 508 and can be expressed as the following equation.

[Equation 3]

A system that applies compensation techniques stops sending and receiving signals and uses a feedback circuit to and Save in real time. As shown in FIG. 4, the reference gain ( ) can be obtained. Thereafter, the gain change data obtained by performing the system performance analysis and compensation technique sequence 404 N times can be expressed as follows.

[Equation 4]

After setting as the reference gain, comparing the measured gains, the signal change amount of the transmission system ( ) can be obtained, and can be expressed as follows.

[Equation 5]

The signal compensation algorithm can be calculated through the PC 513, and the gain change of the N transmission system can be compensated in real time.

Figure 6 schematically shows the structure of a receiving system for direct frequency conversion that includes a feedback circuit for applying a compensation technique according to an embodiment of the present invention.

As shown in FIG. 6, the receiving system 600 for direct frequency conversion including a feedback circuit for applying a compensation technique according to an embodiment of the present invention includes a receiving system using the direct frequency conversion method of FIG. 2. A feedback circuit was added to detect changes in the characteristics of the internal elements of the system.

The receiving system 600 for direct frequency conversion including a feedback circuit for applying the compensation technique according to an embodiment of the present invention includes an ADC 601 and a frequency down-converting mixer ( 602), an oscillator 603 for the LO signal, and a bandpass filter 604 for removing spurious signals. In addition, for the role of a receiving system, the receiving system 600 for direct frequency conversion, which includes a feedback circuit for applying a compensation technique, further includes an LNA 608, an isolator 607, and an RF bandpass filter 605. can do.

The feedback circuit can be implemented based on the LNA 608, which controls the performance of the receiving system for direct frequency conversion. The feedback circuit includes a first RF switch 606 that determines the RF reception or compensation circuit, a second RF switch 609, and a third RF switch 610 that determines whether the LNA 608 passes. The IF signal used in the compensation circuit is generated in the DAC 612, passes through the directional coupler 615, and then generates an RF signal in the millimeter wave band through the frequency up-converting mixer 611, which can be used in compensation techniques. .

Specifically, when the system operates to receive RF signals, it proceeds to Path1 as shown in FIG. 6. Path1 includes a second RF switch 609, an LNA 608, an isolator 607, a first RF switch 606, an RF bandpass filter 605, a frequency down-converting mixer 602, and spurious signal removal. The process may proceed in the order of the bandpass filter 604 and the ADC 601. Depending on the embodiment, the order (arrangement) of each element may change.

Figure 7 shows the RF signal path of a receiving system for direct frequency conversion to measure the amount of change in the system through a feedback circuit according to an embodiment of the present invention.

Referring to FIG. 7, it shows the RF signal path of the receiving system 700 for direct frequency conversion for measuring the amount of change in the system through a feedback circuit according to an embodiment of the present invention, and is a feedback circuit for applying a compensation technique. The structure of the receiving system for direct frequency conversion included is the same as in FIG. 6. In the case of the receiving system, Path2 (402) and Path3 (403) in FIG. 4 are shown as an example to analyze characteristics before and after passing through the amplifier 708, as shown in FIG. 7. .

Path2 and Path3 in FIG. 7 are configured based on the LNA 708, which has the greatest impact on the performance of the receiving system 700.

Path2 generates an IF signal in the DAC 712, and then uses a directional coupler 715, a frequency up-converting mixer 711, a third RF switch 710, a first RF switch 706, and an RF bandpass filter ( 705), a frequency down-converting mixer 702, an IF bandpass filter 704, and a gain/phase detector 714. At this time, the coupled signal of the directional coupler 715 can be input to the gain/phase detector 714 and used as a reference signal.

Path3 is an RF path configured to pass through the LNA (708) in Path2, and includes a DAC (712), a directional coupler (715), a frequency up-converting mixer (711), a third RF switch (710), and a second RF switch (709). ), LNA (708), isolator (707), first RF switch (706), RF band pass filter (705), frequency down-converting mixer (702), IF band pass filter (704), and gain/phase detector Includes (714). Depending on the embodiment, the order of elements configured in each RF path may change.

As shown in [Equation 1] to [Equation 4] for calculating the performance change of the transmitting system, the performance change can be obtained from Path2 and Path3 in the receiving system, and can be expressed as the following equation.

[Equation 6]

here, are the magnitude and phase of the signal after the IF signal generated by the DAC 712 passes through the directional coupler 715.

Second, the signals that passed through Path2 and Path3 respectively are It can be expressed as, and can be expressed as the following equation.

[Equation 7]

here, and are the magnitude and phase of the signal after passing through Path2 and Path3, respectively. In the gain/phase detector 714 via and The power difference ( )and and The power difference ( ) can be calculated.

The first measured value after operating the system and The difference value is the reference gain ( ) can be set. and The difference includes gain information of the LNA 708. If N compensation techniques are applied based on the reference gain, the gain change of the receiving system can be calculated in real time as follows.

[Equation 8]

Each implemented compensation technique can calculate the gain change in real time and compensate for system performance.

At this time, the signal analysis computer 713 shown in FIG. 7 and the computer 513 shown in FIG. 5 can be used as separate computers or as a single computer.

Figure 8 schematically shows a gain/phase detector for comparing and analyzing data of a signal obtained through a feedback circuit according to an embodiment of the present invention.

As shown in FIG. 8, the IF signals to be compared and analyzed are input to the first LOG amplifier 801 and the second LOG amplifier 802, respectively, and differences in signal magnitude and phase are detected. More specifically, the first IF signal (IF signal 1) is input to the first LOG amplifier 801 to detect the difference in size and phase of the signal, and the second IF signal (IF signal 2) is input to the second LOG amplifier (801). 802), the difference in size and phase of the signal is detected.

The gain/phase detector 800 ensures that there is a one-to-one correspondence between the signal magnitude difference and the voltage VMAG value, or the phase difference and the voltage VPHASE value. The output signal of the first LOG amplifier 801 calculates the difference in magnitude between the two IF signals (IF signal 1 and IF signal 2) through the synthesizer 803 and the first voltage conversion structure 804. Additionally, the phase difference of the IF signals is calculated through the mixer 805 for phase difference detection and the second voltage conversion structure 806. Therefore, the magnitude difference and phase difference of IF signals can be obtained inversely through VMAG and VPHASE, and at this time, ADC and MCU for voltage analysis can be used.

The system performance compensation technique using a feedback circuit according to an embodiment of the present invention can measure the performance of a system including active elements sensitive to temperature and experimental environment in real time. As a result, the amount of performance change can be derived, and by compensating for this, a stable system implementation is realized. This is an essential technology for RF systems that must maintain accurate performance, and includes real-time system performance compensation techniques. System compensation feedback circuits and compensation algorithms can be applied to various fields that require a stable system, such as beamforming using an array antenna system, multibeam technology, and radar.

Embodiments of the present invention can be applied as a compensation technique to prevent performance from changing depending on temperature in systems using multiple channels, such as MIMO. For example, in a system that implements beamforming and multiple beams for satellite communication, it can be used as a technique to synchronize all channels before controlling the size and phase of the signal for each channel. Additionally, it can be applied to RF systems and antenna measurement systems that require accurate performance measurement.

In the above, when a component is referred to as being “connected” or “connected” to another component, it may be directly connected to or connected to the other component, but other components may exist in between. It must be understood that there is. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

In addition, terms such as “…unit” and “…module” used in the specification refer to a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

In addition, the components of the embodiments described with reference to each drawing are not limited to the corresponding embodiments, and may be implemented to be included in other embodiments within the scope of maintaining the technical spirit of the present invention, and may also be included in separate embodiments. Even if the description is omitted, it is natural that a plurality of embodiments may be re-implemented as a single integrated embodiment.

In addition, when describing with reference to the accompanying drawings, identical or related reference numerals will be given to identical or related elements regardless of the reference numerals, and overlapping descriptions thereof will be omitted. In describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

As described above, although the embodiments have been described with limited examples and drawings, various modifications and variations can be made by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims (15)

In an RF (Radio Frequency) system using a signal compensation feedback circuit and algorithm to stabilize system performance,
A first step of transmitting and receiving an RF signal in the RF system, a second step of acquiring the size and phase of the RF signal for a path before passing through the amplifier inside the RF system among the transmitting and receiving paths of the RF signal, the RF signal The RF signal for a path including a frequency down-converting mixer and a gain and phase detector in addition to the transmission and reception path - the path including the frequency down-converting mixer and the gain and phase detector refers to the path after passing through the amplifier. A third step of obtaining the magnitude and phase, the difference between the magnitude and phase of the RF signal for the path before passing through the amplifier and the magnitude and phase of the RF signal for the path after passing through the amplifier as gain. A fourth step of measuring, a fifth step of calculating the amount of change in the gain according to an increase in the number of repetitions from the initial gain by repeating the first to fourth steps a plurality of repetitions, the calculated amount of change in the gain In order to perform a signal compensation technique including a sixth step of compensating the size and phase of the RF signal transmitted and received in the RF system, a path before passing through the amplifier and the amplifier are installed in the input and output portion of the amplifier. A feedback circuit containing an RF switch and a directional coupler that forms the path after passing through
RF system, including. delete delete delete delete delete delete delete In a method of operating an RF (Radio Frequency) system using a signal compensation feedback circuit and algorithm for stabilizing system performance,
Installed in the input/output part of the amplifier inside the RF system, it includes a frequency down-converting mixer and a gain and phase detector in addition to the path before passing through the amplifier among the transmission and reception paths of the RF signal in the RF system and the transmission and reception path of the RF signal. Performing signal compensation using a feedback circuit including an RF switch and a directional coupler forming a path - the path including the frequency down-converting mixer and the gain and phase detector refers to the path after passing the amplifier.
Including,
The step of performing the signal compensation is,
A first step of transmitting and receiving the RF signal in the RF system;
A second step of obtaining the magnitude and phase of the RF signal for the path before passing through the amplifier;
A third step of acquiring the magnitude and phase of the RF signal for the path after passing through the amplifier;
A fourth step of measuring the difference between the magnitude and phase of the RF signal for the path before passing through the amplifier and the magnitude and phase of the RF signal for the path after passing through the amplifier as gain;
a fifth step of repeating the first to fourth steps a plurality of repetitions to calculate a change in the gain according to an increase in the number of repetitions from the initial gain;
A sixth step of compensating the size and phase of the RF signal transmitted and received in the RF system by the amount of change in the calculated gain.
A method of operating an RF system, including.
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