CN102043090A - Measurement system for frequency-shift signal parameter of track circuit - Google Patents
Measurement system for frequency-shift signal parameter of track circuit Download PDFInfo
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- CN102043090A CN102043090A CN2009102185073A CN200910218507A CN102043090A CN 102043090 A CN102043090 A CN 102043090A CN 2009102185073 A CN2009102185073 A CN 2009102185073A CN 200910218507 A CN200910218507 A CN 200910218507A CN 102043090 A CN102043090 A CN 102043090A
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Abstract
The invention relates to an online measurement system for the frequency-shift keying signal parameter of a track circuit. Frequency-shift keying (FSK) signals of the track circuit are first subjected to filtration by a bandstop filtering circuit and a low-pass filtering to filter power frequency interference and high-frequency noise effectively and then shaped by a non-zero-crossing comparison circuit to form square wave signals; the shaped square wave signals are counted at a high speed by a field programmable gate array (FPGA), a high-speed counting result is stored into a dual-port random-access memory (RAM), and data in the dual-port RAM are sent to an advanced reduced instruction set computer (RISC) machine (ARM) processor through an analog serial port; and the ARM processor compensates distortion data generated at the switching point of upper and lower side frequency so as to demodulate the frequency of low-frequency modulating signals and carrier signals. In the system, the FPGA and the ARM7 processor are used, so the measuring speed of the frequency-shift signals is high, the measurement range is large and the accuracy is high; and the parameter measurement system compensate the distortion data and measuring error effectively, so the system has a certain fault-tolerant capability, and can meet the requirement of the FSK signal parameter measurement of the track circuit.
Description
Technical field
The present invention is a railway traffic system middle orbit circuit frequency shift keying signal parameter measurement system, is used for the automatic measurement of track circuit FSK frequency shift keying signal parameter, relates to the frequency shift modulated track circuit Automatic Measurement Technique.
Background technology
In the railway traffic system, utilize the frequency shift keying signal inspection to have or not between train, transmission train occupation information and realization ground and train usually and exchange information.The track frequency shift keying signal is that the high-low level of a kind of usefulness low frequency signal (modulation signal) is distinguished gating high-frequency signal (CF signal) and generation.At present, the track frequency shift keying circuit of domestic main employing has homemade frequency shift modulated track circuit signal and introduces the UM71 non-insulated track circuit.The low frequency modulations frequency of homemade frequency shift modulated track circuit has been chosen 18 kinds as the low frequency modulations frequency in from 10.3Hz to 29Hz, introduces UM71 low frequency modulations frequency and has chosen 18 kinds as the low frequency modulations frequency in from 7Hz to 29Hz.The signal that track circuit provides is as running token, and the driver is fully according to this signal manipulation train operation.Development is stable, reliable detection equipment detects the track-circuit signalling parameter in real time, accurately, guarantees that track-circuit signalling is subjected to real-time monitoring, in time finds potential faults, and is significant for safe train operation.
Track circuit FSK frequency shift keying signal is a kind of periodic signal, and the measuring method of current employing can be divided into frequency domain method and time domain approach two classes.Frequency domain method is frequency-discrimination method, usually adopt frequency spectrum analysis method that track-circuit signalling is analyzed, need carry out integer-period sampled to track signal when this method is carried out the FFT conversion, and not only has the advantage of digital communication in the track-circuit signalling of reality, and have the characteristics of non-linear modulation, therefore be difficult to satisfy all carry out integer-period sampled to all signals.In addition, though Spectral Analysis Method can be measured the frequency parameter and the effective value parameter of signal, but lost carrier frequency and frequency deviation information, and then can not determine the upper and lower side frequency of signal.Thereby utilize conventional frequency spectrum analysis method that all track-circuit signallings are carried out real-time high-precision and detect and have the certain difficulty of existence.In recent years, in the domestic correlative study relatively the forward position be to have proposed utilization modern spectrum estimated parameter detection method.Its basic thought is in composing estimation procedure the finite data that observes not to be made any discriminating hypotheses, how these data is being produced on the basis with certain priori, adopts extrapolation or forecast method, infers and obtains later data.Wherein comparative maturity is Burg method in the modern spectral estimation method.The somebody is attempting short time discrete Fourier transform and wavelet transformation even Fractal Theory Applications in the detection of track signal in addition.Though the research of these theoretical sides has obtained certain achievement, apply it to and also need go further effort in the actual engineering.
Time domain approach adopts frequency-shift signaling zero passage cycle detection method more.The modulating frequency of cab signal its numerical value within i.e. half modulation period of a period of time can not change, it is less demanding to real-time, thereby we can utilize during this period of time and handle with interior whole signals, and then can increase and utilize software to carry out the possibility that mathematical method is handled.Zero passage cycle detection method is carried out according to these characteristics.The processing procedure of frequency-shift signaling zero passage cycle detection method is: at first frequency-shift signaling is carried out Filtering Processing, after power frequency interference and most of noise filtering, form square-wave signal through shaping, count to get a counting sequence N by counter then
1, N
2, N
n, carry out each parameter that software demodulation obtains signal by the CPU processing unit at last.This time domain detection method has tangible chronergy, and the quality of signal and the stability of count pulse are had higher requirement, and is also higher to the requirement of signal prefilter.Under little noise conditions, the time area detecting method measuring accuracy depend primarily on the frequency size of high-frequency count clock, the big more then precision of frequency is high more.Current time domain detection method mainly adopts single-chip microcomputer to carry out the parameter measurement that the zero passage cycle detection realizes track signal.Because the single-chip microcomputer frequency of operation is lower, the counting clock frequency is lower, so actual measurement precision and result are relatively poor.When containing bigger noise in the signal, undesired signal can change the zero crossing position of original signal, causes measurement result and precision sharply to descend.
Summary of the invention
The present invention has provided a kind of track circuit frequency shift keying signal measurement scheme, system with a high-performance FPGA and ARM as the core processor unit, the prime signal processing circuit comprises signal filtering and shaping, carry out frequency discrimination then, and operation result is outputed to LCD go up to show, track-circuit signalling parameter measurement system structured flowchart is seen Fig. 1, FPGA mainly finishes the square-wave signal by the fsk signal conversion is carried out counting complete cycle, and deposit count results in inner dual port RAM and cushion, then data are sent into that ARM handles and software demodulation; The precision of systematic survey square-wave cycle is decided by that to a great extent high frequency quantizes the size of clock, if it is too big that high frequency quantizes clock, then the width of count value increases, the ram cell that needs during stored count value increases, native system adopts the clock of 30M high frequency high stable to carry out counting complete cycle, effectively guaranteed the measuring accuracy of system, the rapidity of FPGA has guaranteed the response speed of system simultaneously; FPGA measurement track-circuit signalling principle is seen shown in Figure 2, and ARM mainly finishes the track-circuit signalling voltage measurement, and the data that FPGA measures are calculated, and measurement result is shown on LCD.
In the present invention, track circuit fsk signal parameter measurement system has following technical characterictic:
(a) adopt FPGA and ARM to realize the fsk signal measurement, traditional time domain measurement mode is a core with single-chip microcomputer or the single CPU of DSP generally, CPU also will bear tasks such as voltage measurement and demonstration in real time the cycle of survey, the real-time of measuring is relatively poor, the cycle of will surveying in the system separates with voltage measurement and demonstration, FPGA is exclusively used in period measurement, and ARM is used for voltage measurement and shows control in real time, has guaranteed the real-time and the high precision of system;
(b) signal adopts non-zero passage manner of comparison to carry out signal shaping, the tradition time domain approach adopts zero passage cycle detection method more, this method is subjected to external interference easily, when there is interference in the external world, produce skew zero point, and it is inaccurate to cause detecting zero position, causes carrier frequency to occur than large deviation, native system adopts a kind of non-zero passage comparative approach to the detection of frequency-shift signaling, and zero migration is not almost exerted an influence to system's accuracy of detection;
(c) utilize FPGA to realize dual port RAM and simulative serial port function, adopt the embedded RAM module M4K of FPGA to realize that dual port RAM is used for metadata cache, guarantee the high-speed bidirectional transmission of data, realize that simulative serial port function and ARM carry out real-time Communication for Power;
(d) utilize arm processor to realize receiving measurement data, and measurement data is carried out demodulation, FPGA send arm processor with measurement data by simulative serial port, carries out software demodulation in ARM;
(e) distortion data and error are compensated, because non-integer-period switched when upper and lower side frequency exchanged, causing point of interface may be on the arbitrfary point of one-period, point of interface may be the latter half of last frequency and the first half combination of back one frequency, point of interface place count value is at random, cause the modulating frequency of system to be measured exactly, see shown in Figure 3ly, suppose that two kinds of upper and lower side frequency signals are f than difficulty
u, f
d, the count value at the theoretical amount clock is respectively C so
u, C
d, C wherein
u=30000000/f
u, C
d=30000000/f
d, two kinds of frequency point of interface place distortion are C
s, C
s=C '
u+ C '
d, C ' wherein
u, C '
dBe respectively the random value C of point of interface place
sBelong to CF signal f
u, f
dPart; According to the continuous feature of track circuit frequency shift keying signal phase place, can obtain
The random count value that can calculate the point of interface place thus is assigned to the component of different CF signal:
This programme implementation result: this frequency shift keying signal measuring system is applicable to the track-circuit signalling of two kinds of standards of ZPW2000 of homemade 18 information and imported technology, and discern automatically, after arm processor receives measurement data, the distortion number is effectively handled, and measurement result shown that with 128 * 64 LCD system can reach following measuring accuracy and technical indicator:
Centre frequency and frequency deviation (or upper and lower side frequency):
Frequency discrimination ability≤0.1Hz
Centre frequency detects error≤0.2Hz
Frequency deviation detects error≤0.2Hz
The low frequency modulations frequency:
Frequency discrimination ability≤0.01Hz
Detect error≤0.03Hz
Frequency-shift signaling voltage:
Voltage measurement resolution≤0.1%
Voltage measurement error≤0.5%
Processing time≤3s
Description of drawings
The required hardware block diagram of accompanying drawing 1 the inventive method;
Accompanying drawing 2FPGA measures track frequency-shift signaling principle;
Accompanying drawing 3 is that high-speed optical signal is to mixed electrical optical conversion of signals process flow diagram.
Embodiment
In the present embodiment, total system is made of prime frequency-shift signaling processing unit, FPGA counting unit, three parts of ARM calculation processing unit, in order to realize accurately measuring the track frequency-shift signaling, needs solution guardian technique problem and embodiment as follows:
Frequency-shift signaling prime signal processing unit mainly is transformed into square-wave signal to original frequency-shift signaling filtering and with the high frequency sinusoidal carrier signal, guarantees that by selecting suitable photoelectric coupled circuit parameter the rising edge of square-wave signal and negative edge are in effective range.
It is to count umber of pulse during each square wave by FPGA that carrier wave and modulating frequency are calculated, then count value being delivered to arm processor handles, though it is many more to measure carrier and modulating signal group number in the processing, result of calculation is accurate more, but measuring period is too much, causes system response time to reduce easily.
Carrier frequency is measured interference protection measure, and carrier signal is measured the time domain approach that adopts non-zero passage detection, has improved the interference rejection ability that frequency-shift signaling is measured.
Distortion data and Error processing, distortion data are to cause to calculate the main cause that upper and lower side frequency is made mistakes, and therefore need sort out the distortion data science of carrying out, and measuring error is compensated.
Claims (3)
1. novel track circuit frequency-shift signaling parameter measurement system, after the track circuit fsk signal is carried out filtering, shaping, utilize high speed FPGA that square-wave signal is carried out high-speed counting, and the result is transferred to ARM by simulative serial port, arm processor compensates the distortion data and the measuring error of carrier signal at upper and lower side frequency switching point place, demodulate the correlation parameter of track circuit fsk signal, it is characterized in that:
A. adopt trap and low-pass filter circuit to carry out filtering, adopt the non-zero passage comparator circuit of high speed to realize signal shaping;
B. utilize FPGA to realize dual port RAM, simulative serial port and pulse width measure function, utilize arm processor to realize distortion data compensation and signal demodulation;
2. filtering as claimed in claim 1, shaping circuit is characterized in that: filtering circuit can the filtering power frequency disturb and high frequency noise, and shaping circuit carries out the high speed shaping to frequency-shift signaling, and the rise time and the fall time of signal are shorter after the assurance shaping;
3. FPGA as claimed in claim 1 and arm processor circuit, it is characterized in that: realize dual port RAM by the inner R4K storage unit of FPGA, utilize VHDL language to realize the simulative serial port function, and data are sent to the ARM processing unit by this simulative serial port, arm processor compensates the data of CF signal at upper and lower side frequency switching point place, demodulates the frequency-shift signaling parameter.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103144656A (en) * | 2011-05-16 | 2013-06-12 | 北京和利时系统工程有限公司 | Train control system on-board equipment and method for demodulating track circuit signal |
| CN103634263A (en) * | 2013-12-07 | 2014-03-12 | 天津光电通信技术有限公司 | Continuous-phase frequency-shift keying digital demodulation device and demodulation method implemented by same |
| CN105516033A (en) * | 2015-07-23 | 2016-04-20 | 中国电子科技集团公司第四十一研究所 | Analog signal demodulation and analysis method based on spectrum analyzer |
| CN106556736A (en) * | 2016-10-25 | 2017-04-05 | 嘉兴职业技术学院 | A kind of multi-functional analyzer |
| CN109194223A (en) * | 2018-10-08 | 2019-01-11 | 湖南航天机电设备与特种材料研究所 | A kind of control system for permanent-magnet synchronous motor for being used to set product from laser for three |
| CN114997247A (en) * | 2022-07-28 | 2022-09-02 | 成都凯天电子股份有限公司 | FPGA-based unmanned aerial vehicle turbine engine rotating speed acquisition method and system |
| CN116962128A (en) * | 2023-09-21 | 2023-10-27 | 北京全路通信信号研究设计院集团有限公司 | Method, device, equipment and storage medium for analyzing frequency shift signal |
-
2009
- 2009-10-23 CN CN2009102185073A patent/CN102043090A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103144656A (en) * | 2011-05-16 | 2013-06-12 | 北京和利时系统工程有限公司 | Train control system on-board equipment and method for demodulating track circuit signal |
| CN103144656B (en) * | 2011-05-16 | 2015-07-01 | 北京和利时系统工程有限公司 | Train control system on-board equipment and method for demodulating track circuit signal |
| CN103634263A (en) * | 2013-12-07 | 2014-03-12 | 天津光电通信技术有限公司 | Continuous-phase frequency-shift keying digital demodulation device and demodulation method implemented by same |
| CN105516033A (en) * | 2015-07-23 | 2016-04-20 | 中国电子科技集团公司第四十一研究所 | Analog signal demodulation and analysis method based on spectrum analyzer |
| CN106556736A (en) * | 2016-10-25 | 2017-04-05 | 嘉兴职业技术学院 | A kind of multi-functional analyzer |
| CN109194223A (en) * | 2018-10-08 | 2019-01-11 | 湖南航天机电设备与特种材料研究所 | A kind of control system for permanent-magnet synchronous motor for being used to set product from laser for three |
| CN114997247A (en) * | 2022-07-28 | 2022-09-02 | 成都凯天电子股份有限公司 | FPGA-based unmanned aerial vehicle turbine engine rotating speed acquisition method and system |
| CN114997247B (en) * | 2022-07-28 | 2022-11-25 | 成都凯天电子股份有限公司 | FPGA-based unmanned aerial vehicle turbine engine rotating speed acquisition method and system |
| CN116962128A (en) * | 2023-09-21 | 2023-10-27 | 北京全路通信信号研究设计院集团有限公司 | Method, device, equipment and storage medium for analyzing frequency shift signal |
| CN116962128B (en) * | 2023-09-21 | 2023-12-08 | 北京全路通信信号研究设计院集团有限公司 | Method, device, equipment and storage medium for analyzing frequency shift signal |
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Application publication date: 20110504 |