CN114265334A

CN114265334A - Automatic simulation loop impedance matching detection method

Info

Publication number: CN114265334A
Application number: CN202010972219.3A
Authority: CN
Inventors: 卢瑞昕
Original assignee: Shenzhen Dinstar Co ltd
Current assignee: Shenzhen Dinstar Co ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2022-04-01
Anticipated expiration: 2040-09-16
Also published as: CN114265334B

Abstract

The invention discloses an automatic analog loop impedance matching detection method, which comprises the following steps: adopting an impedance automatic matching system formed by mutual interaction of a DSP processing system based on a CPU and an SLIC chip to automatically carry out impedance matching between a subscriber loop transmission line and a signal source so as to obtain an optimal matched impedance signal; the best matched impedance value is set into the SLIC to optimize the quality of the signal transmitted to the SPC switch. The invention can reduce the manual testing intensity, reduce the testing time and improve the matching accuracy, thereby improving the communication quality, improving the tone quality level of the communication, reducing the noise and improving the communication quality and the communication success rate of the communication equipment such as a fax machine, a pos machine and the like of the data terminal.

Description

Automatic simulation loop impedance matching detection method

Technical Field

The invention relates to the field of communication, in particular to a method for automatically matching impedance of a telephone line by using reflected signal strength, and specifically relates to a method for automatically detecting impedance matching of an analog loop.

Background

The prior voip simulation gateway adopts a special interface chip to realize the BORSCHT function of a simulation user loop, namely, an slic interface chip of a simulation telephone is utilized; in practical engineering application, due to reasons such as a path through which a line passes, a material of the line, a thickness of the line, a length of the line, and a subscriber loop impedance of a local side switch to which the line is connected, impedance configured by a gateway is unmatched, so that voice quality is poor, noise is generated, a fax effect is poor, and modem communication is wrong.

For the condition slic, a register is used for impedance matching, so that the communication effect is improved, but because the characteristics of various lines are inconsistent, even in the same country and the same city, the impedance of the same project is not matched due to the characteristics of the lines, so that the communication effect is reduced.

In the past, parameters of a matching register are generally configured manually and tested continuously to achieve a relatively good effect, so that the processing is time-consuming and labor-consuming, and the final result is not necessarily the best; the invention is optimized aiming at the situation, and achieves better impedance matching through automatic impedance detection, thereby improving the use effect of users.

Disclosure of Invention

The invention aims to provide an automatic simulation loop impedance matching detection method, which aims to solve the problem that the time and labor are wasted when the parameters of a matching register are configured manually in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

an automatic analog loop impedance matching detection method, the automatic impedance matching method includes the following steps:

adopting an impedance automatic matching system formed by mutual interaction of a DSP processing system based on a CPU and an SLIC chip to automatically carry out impedance matching between a subscriber loop transmission line and a signal source so as to obtain an optimal matched impedance signal, wherein the DSP processing system based on the CPU comprises the CPU and the DSP which are mutually and interactively connected;

the best matched impedance value is set to the telephone interface chip of the device and the SPC exchange will receive the best signal and improve the communication quality.

Further, the impedance matching system judges the impedance matching degree in an echo detection mode, and the impedance matching method of the impedance matching system is as follows:

s1, the CPU sends an instruction to set an impedance signal value;

s2, sending DTMF signal to the user loop by DSP, and transmitting to SLIC chip by PCM data bus; judging whether the DTMF signal exists according to the output signal, if so, executing step S3, otherwise, executing step S1;

s3, the DSP processor detects the reflected DTMF signal on the PCM data bus, and when the DSP detects the reflected echo, the signal matching is carried out;

s4, detecting the amplitude of the signal after the signal is matched, and recording the amplitude of the impedance and the reflected signal by measuring the amplitude of the echo to finish one-time test;

s5, continuously reducing the impedance on the SLIC chip by using the CPU to send instructions, carrying out similar tests, repeating the steps S1-S4, carrying out DTMF signal detection, measuring the echo amplitude, and acquiring more than two groups of impedance and reflected DTMF signal data; if the detection count is completed, executing step S6, and if the count is not completed, executing step S1;

and S6, obtaining a lowest echo amplitude in a plurality of groups of test data, automatically searching the impedance with the lowest echo amplitude as the best matched impedance signal value by the CPU-based DSP processing system and the SLIC chip, and setting the best impedance signal value to finish the test and finish the automatic impedance matching work.

Furthermore, the CPU is connected to the SLIC chip through a local data bus, and the local data bus is used for transmitting a CPU control signal.

Further, the PCM data bus is a digital voice path to the CPU for transmitting voice data signals.

Furthermore, the SLIC chip adopts a chip science and technology brand SI3215 type chip, is used for providing an analog subscriber loop interface to realize the fusion of the communication device gateway and the impedance data network, and comprises a control interface, a PCM interface, a tone generator, an analog-digital and digital-analog conversion circuit, a hybrid circuit, two lines of TIP and RING, and a discrete line driving circuit formed by discrete components.

Further, the DTMF signal transmitted to the SLIC chip is decoded by the SLIC chip and then transmitted to the TIP and RING lines.

Further, a dual-port RAM is arranged between the CPU and the DSP, and the dual-port RAM is used to implement data conversion between the CPU and the DSP, where the data conversion includes voice data conversion and control data conversion.

The invention has the beneficial effects that:

the automatic simulation loop impedance matching detection method provided by the invention is used for carrying out automatic user loop impedance detection, achieving better impedance matching, reducing noise, artificial test intensity and test time, improving matching accuracy, further improving communication quality and conversation tone quality level, improving user using effect, and improving communication quality and communication success rate of communication equipment such as a fax machine and a pos machine of a data terminal.

Drawings

FIG. 1 is a schematic diagram of an automatic impedance matching application of the present invention;

FIG. 2 is a flow chart of the automatic impedance matching of the present invention;

fig. 3 is a functional block diagram of a subscriber loop interface circuit of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and are only used for explaining the present invention, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, the present invention provides a technical solution: an automatic simulation loop impedance matching detection method comprises the following steps:

Specifically, the impedance automatic matching system judges the impedance matching degree in an echo detection mode, wherein the higher the echo amplitude of the echo detection mode is, the lower the impedance matching degree is, and conversely, the higher the impedance matching degree is, the lower the echo amplitude is.

The impedance matching method of the impedance automatic matching system comprises the following steps:

s1, sending an instruction to set an impedance signal value through the CPU;

s3, the DSP processor detects the reflected DTMF signal on the PCM data bus, and when the DSP detects the reflected echo, the signal matching is carried out; DTMF signals transmitted to the SLIC chip are decoded by the SLIC chip and then transmitted to TIP and RING lines;

It should be noted that the DSP processing system based on the CPU provided in this embodiment is a control system that integrates the CPU and the DSP, so as to greatly increase the sending speed of the instruction, facilitate the impedance matching system to perform automatic control, and implement automatic impedance matching.

Specifically, the CPU is connected to the SLIC chip through a local data bus, and the local data bus is used for transmitting a CPU control signal; the PCM data bus is a digital voice channel to the CPU and is used for transmitting voice data signals; the dual-port RAM is arranged between the CPU and the DSP and used for realizing data conversion between the CPU and the DSP, and the data conversion comprises voice data conversion and control data conversion.

It should be noted that the DSP provided in this embodiment adopts a 32-bit digital signal processor of ADSP21020 type or TMS320C3X type; the CPU adopts a 32-bit processor based on an MIPS4kc-RISC core and is used for buffering instructions and data to complete the control of an impedance automatic matching system, and the CPU has the support of 4K-byte I-cache, 4K-byte D-cache and MMU.

Specifically, the SLIC chip adopts a chip science and technology brand SI3215 type chip, the SLIC chip is used for providing an analog subscriber loop interface to realize the fusion of a communication device gateway and an impedance data network, and the SLIC chip comprises a control interface, a PCM interface, a tone generator, an analog-digital and digital-analog conversion circuit, a hybrid circuit, two lines of TIP and RING, and a discrete line driving circuit composed of discrete components; wherein, the SLIC chip includes but is not limited to the chip science and technology brand SI3215 type chip, other brands such as Nissan chemistry, Cree company, crystal electricity, optical epitaxy, Spanish, Sanan brand series and SLIC chips of various types are also suitable for the impedance matching method of the invention; the structure and principle of the SLIC chip are well known in the market, and the control interface, the PCM interface, the tone generator, the analog-to-digital and digital-to-analog conversion circuit, the hybrid circuit, the TIP and RING two lines, and the discrete line driving circuit formed by discrete components are conventional circuit technologies in the conventional SLIC chip, and therefore are not described herein again.

It should be noted that the DSP provided in this embodiment is an english abbreviation of a digital signal processor, and is a fast and powerful microprocessor, the DSP can perform fast mathematical operations on a digital signal stream, and calculate impedance signal values matched between a subscriber loop transmission line and a signal source through a mathematical operation matching control algorithm, the mathematical operations are impedance matching control algorithms, the mathematical operations include simple addition and subtraction and multiplication to complex filtering and signal analysis functions, such as fast fourier transform and discrete cosine transform, and the DSP is embedded in an impedance automatic matching system.

The DSP works by receiving analog signals to convert them into digital signals of 0 or 1, modifying, deleting, and enhancing the digital signals, and interpreting the digital data back to analog data or actual environment format in the SLIC system chip.

Wherein, DTMF is the abbreviation of dual-tone multifrequency English; SLIC is English abbreviation of subscriber loop interface circuit, SLIC chip is analog telephone line interface circuit chip; the CPU is an acronym of the central processing unit, and mainly comprises an arithmetic unit, a controller, a register set, an internal bus and the like.

In summary, in the impedance matching detection method provided in this embodiment, the reflected echo is detected by the DTMF signal sent by the DSP, a lowest amplitude is obtained in multiple sets of test data by measuring the amplitude of the echo, and the impedance is defined as a finally matched impedance, and is transmitted to the SLIC chip through the PCM data bus, and the signal is sent to the TIP and RING two lines through decoding of the SLIC chip, at this time, the DSP monitors the reflected DTMF signal on the PCM data bus, and if the signals are matched, detects the amplitude thereof; by continuously setting the impedance on the SLIC chip and carrying out similar tests, a group of impedance and data of the reflected DTMF signals are finally obtained, and the impedance with the lowest reflected signal amplitude is selected as the optimal matching impedance.

The automatic simulation loop impedance matching detection method provided by the invention is used for carrying out automatic user loop impedance matching, reducing the manual testing intensity, reducing the testing time and improving the matching accuracy, and the communication tone quality of the gateway is greatly improved after impedance matching, the noise is reduced, and the fax/pos reliability is improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. an automatic analog loop impedance matching detection method, is characterized in that, described automatic impedance matching method comprises the steps:

The impedance automatic matching system formed by the interaction between the CPU-based DSP processing system and the SLIC chip is used to automatically perform impedance matching between the user loop transmission line and the signal source to obtain the best matched impedance signal. The CPU-based DSP The processing system includes a CPU and a DSP that are interconnected and connected to each other;

Send the test signal to the traditional analog transmission line, because when the impedance does not match, the transmission system will reflect the signal. By checking the reflected signal, it can automatically match the transmission line and the transmission system composed of the program-controlled switch. The optimal impedance value of the system.

2. automatic analog loop impedance matching detection method according to claim 1, is characterized in that: described impedance automatic matching system judges the impedance matching degree by the mode of echo detection, and the impedance matching method of impedance automatic matching system is as follows:

S1. The CPU sends an instruction to set the impedance signal value;

S2, adopt DSP to send DTMF signal to user loop, utilize PCM data bus to transmit on SLIC chip; Judge whether DTMF signal exists according to the output signal, if yes, then execute step S3, if not, execute step S1;

S3. The DSP processor detects the reflected DTMF signal on the PCM data bus, and performs signal matching when the DSP detects the reflected echo;

S4. When the signal is matched, its amplitude is detected, and the impedance and reflected signal amplitude are recorded by measuring the echo amplitude to complete a test;

S5. Use the CPU to send instructions to continuously adjust the impedance on the SLIC chip, and perform similar tests, repeat steps S1-S4, perform DTMF signal detection, measure the echo amplitude, and obtain more than two groups of impedance and reflected DTMF signal data ; If the detection count is completed, then step S6 is performed, and if the count is not completed, then step S1 is performed;

S6. Obtain a minimum echo amplitude in multiple sets of test data. The CPU-based DSP processing system cooperates with the SLIC chip to automatically find the impedance with the lowest echo amplitude as the best matched impedance signal value, and set the best impedance signal value. This ends the test and completes the automatic impedance matching work.

3. The automatic analog loop impedance matching detection method according to claim 1 or 2, characterized in that : using the intensity of the reflected signal between the detection device and the transmission system to automatically match the impedance of the SLIC.

4 . The automatic analog loop impedance matching detection method according to claim 2 , wherein the PCM data bus is a digital voice path to the CPU for transmitting voice data signals. 5 .

5. automatic analog loop impedance matching detection method according to claim 1, is characterized in that: described SLIC chip adopts core science and technology brand SI3215 type chip, and this SLIC chip is used to provide analog user loop interface to realize communication equipment The fusion of gateway and impedance data network, and SLIC chip includes control interface, PCM interface, tone generator, analog-to-digital and digital-to-analog conversion circuit, hybrid circuit, TIP and RING two lines, and discrete line driver composed of discrete components circuit.

6 . The automatic analog loop impedance matching detection method according to claim 2 , wherein the DTMF signal transmitted to the SLIC chip is decoded by the SLIC chip and transmitted to the TIP and RING lines. 7 .

7. The automatic analog loop impedance matching detection method according to claim 1, wherein a dual-port RAM is provided between the CPU and the DSP, and the dual-port RAM is used to realize data conversion between the CPU and the DSP , and its data conversion includes voice data conversion and control data conversion.