RU44626U1 - TONAL RAIL CHAIN RECEIVER - Google Patents

Abstract

The utility model relates to devices of railway automation and telemechanics, namely to receivers of tonal rail circuits that monitor the condition of the railway track. The receiver of the tone rail circuit contains a bandpass filter, a buffer stage, an amplitude demodulator, a first resolver, a symmetric amplitude limiter, a frequency demodulator, a shift register, a phase locked loop, a digital comparator, an expected codeword block, a key, an amplifier, a second resolver, moreover, the output of the bandpass filter is connected to the input of the buffer cascade, the output of which is connected to the input of the amplitude demodulator, the output of which is connected to the input of the first solving device, the output of the latter is connected to the first input of the key, a symmetric amplitude limiter, the input of which is connected to the output of the bandpass filter, and the output to the input of the frequency demodulator, the output of which is connected to the first input of the shift register and to the input of the phase locked loop, the output of which is connected to the second input shift register, the output of which is connected to the first input of the digital comparator, to the second input of which the expected codeword block is connected, the output of the digital comparator is connected to the second input key Whose output via an amplifier connected to the input of the second resolver. Additionally, a unit for averaging the carrier signal amplitude, a scaling amplifier and an adaptive amplitude limiter were introduced, the input of the averaging unit for the carrier signal amplitude being connected to the output of the amplitude demodulator, and the output to the input of the scaling amplifier, the output of which is connected to the second input of the adaptive

an amplitude limiter, the output of which is connected to the input of the bandpass filter, and an input signal is supplied to the first input of the adaptive amplitude limiter. The receiver of the tone rail circuit can be successfully used in self-locking devices with tone rail chains; its use allows to increase the stability of the operation of interval train control systems.

Description

The utility model relates to devices of railway automation and telemechanics, namely to receivers of tonal rail circuits that monitor the condition of the railway track.

A known tone rail circuit receiver comprising a bandpass filter, a buffer stage, an amplitude demodulator, a first solver, a symmetric amplitude limiter, a frequency demodulator, a shift register, a phase locked loop, a digital comparator, an expected codeword block, a key, an amplifier, a second solver .

The band-pass filter selects the carrier signal of the tone rail circuit, which is fed to the input of the amplitude demodulator through the buffer stage and to the input of the symmetric amplitude limiter. From the output of the amplitude demodulator, the envelope of the signal of the tone rail circuit is fed to the input of the first solver, which makes a decision about the presence or absence of the carrier signal of the tone rail circuit and, in accordance with this, controls the key.

From the output of the symmetric amplitude limiter, which suppresses spurious filtering products, the signal is fed to the input of the frequency demodulator, which, in turn, extracts the code component of the signal of the tone rail circuit. From the output of the frequency demodulator, the signal is fed to the first input of the shift register and to the input of the phase locked loop. The phase locked loop extracts a clock signal from the received code component, by which the code word is entered in the shift register. From register exit

the received codeword is received at the first input of the digital comparator, which compares it with the codeword recorded in the expected codeword block. If the received code word coincides with the expected one, the signal from the output of the digital comparator is fed to the second input of the key.

If the first solver decides on the presence of a carrier signal at the input of the receiver, the key is opened and the signal from the output of the digital comparator is fed through the amplifier to the input of the second solver, which makes the final decision on the presence (absence) of the tone rail circuit signal at the input of the receiver. [Utility Model Patent No. 39561. Tone Rail Chain Receiver].

The disadvantage of this receiver rail track circuit is that it has insufficient noise immunity when exposed to pulsed noise traction current and atmospheric overvoltage at its input.

This technical solution is selected as a prototype.

The technical result of the proposed device is to increase the reliability of information about the state of the monitored sections of the track by increasing its noise immunity when exposed to pulsed interference.

The technical result is achieved by the fact that in the receiver of the tone rail circuit containing a bandpass filter, a buffer stage, an amplitude demodulator, a first solver, a symmetric amplitude limiter, a frequency demodulator, a shift register, a phase locked loop, a digital comparator, an expected codeword block, a key , an amplifier, a second deciding device, wherein the output of the bandpass filter is connected to the input of the buffer stage, the output of which is connected to the input of the amplitude demodulator, the output of which

connected to the input of the first deciding device, the output of the last connected to the first input of the key, a symmetric amplitude limiter, the input of which is connected to the output of the bandpass filter, and the output to the input of the frequency demodulator, the output of which is connected to the first input of the shift register and to the input of the phase locked loop whose output is connected to the second input of the shift register, the output of which is connected to the first input of the digital comparator, to the second input of which the expected codeword block is connected, the digital output of the second comparator is connected to the second input of the key, the output of which through the amplifier is connected to the input of the second deciding device, an additional averaging block of the carrier signal amplitude, a scaling amplifier and an adaptive amplitude limiter are introduced, the input of the averaging block of the carrier signal amplitude connected to the output of the amplitude demodulator, and the output to the input of the scaling amplifier, the output of which is connected to the second input of the adaptive amplitude limiter, the output of which is connected to the input of the bandpass filter pa, wherein the input signal is supplied to a first input of adaptive amplitude limiter.

Figure 1 presents the functional diagram of the receiver tone rail circuit.

The receiver of the tone rail circuit contains an adaptive amplitude limiter 1, a bandpass filter 2, a buffer stage 3, an amplitude demodulator 4, an averaging block for the amplitude of the carrier signal 5, a scaling amplifier 6, a first decoding device 7, a key 8, a symmetric amplitude limiter 9, a frequency demodulator 10, shift register 11, phase locked loop 12, expected codeword block 13, digital comparator 14, amplifier 15, second resolver 16.

The receiver tone rail circuit operates as follows. The signal of the tone rail circuit is fed to the input of the adaptive amplitude limiter 1, which limits the amplitude of the impulse noise at the threshold sensitivity level of the receiver. From the output of the amplitude limiter, the resulting signal is fed to the input of the bandpass filter 2, which selects the carrier signal of the tone rail circuit. From the output of the bandpass filter 2, the signal is fed to the input of the amplitude demodulator 4 through the buffer stage 3 and to the input of the symmetric amplitude limiter 9. The signal from the output of the amplitude demodulator 4 is fed to the input of the averaging unit of the amplitude of the carrier signal 5 and to the input of the first solving device 7. From the output of the block averaging the amplitude of the carrier signal 5, the average value of the amplitude of the envelope of the signal is fed to the input of the scaling amplifier 6, which controls the adaptive amplitude limiting threshold with its output signal og limiter 1. Thus, the automatic control of the threshold limit impulse noise in excess of the current amplitude of the envelope of the signal. The first decision device 7 makes a decision about the presence or absence of the carrier signal of the tone rail circuit and, in accordance with this, controls the key 8 at the first input.

The signal from the output of the symmetric amplitude limiter 9, which suppresses spurious filtering products, is fed to the input of the frequency demodulator 10, which, in turn, extracts the code component of the signal of the tone rail circuit. From the output of the frequency demodulator 10, the signal is fed to the first input of the shift register 11 and to the input of the phase locked loop 12. The phase locked loop 12 extracts a clock signal from the received code component, by which the code word is entered into shift register 11. From the output of shift register 11, the received the codeword

arrives at the first input of the digital comparator 14, which compares it with the code word recorded in the block of the expected code word 13. When the received code word coincides with the expected, the signal from the output of the digital comparator 14 is fed to the second input of the key 8.

If the first solver 7 makes a decision on the presence of a carrier signal at the input of the receiver, the key 8 is opened and the signal from the output of the digital comparator 14 is fed through an amplifier 15 to the input of the second solver 16, which makes the final decision on the presence (absence) of the tone rail circuit signal on receiver input.

The receiver of the tone rail circuit can be successfully used in self-locking devices with tone rail chains; its use allows to increase the stability of the operation of interval train control systems.

Claims (1)

Tone rail circuit receiver comprising a bandpass filter, buffer stage, amplitude demodulator, first resolver, symmetric amplitude limiter, frequency demodulator, shift register, phase locked loop, digital comparator, expected codeword block, key, amplifier, second resolver, moreover, the output of the bandpass filter is connected to the input of the buffer cascade, the output of which is connected to the input of the amplitude demodulator, the output of which is connected to the input of the first solving devices , the output of the latter is connected to the first input of the key, a symmetric amplitude limiter, the input of which is connected to the output of the bandpass filter, and the output to the input of the frequency demodulator, the output of which is connected to the first input of the shift register and to the input of the phase-locked loop, the output of which is connected to the second the input of the shift register, the output of which is connected to the first input of the digital comparator, to the second input of which the expected codeword block is connected, the output of the digital comparator is connected to the second input of the cha, the output of which through the amplifier is connected to the input of the second solver, characterized in that it additionally includes a block of averaging the amplitude of the carrier signal, a scaling amplifier and an adaptive amplitude limiter, and the input of the block of averaging the amplitude of the carrier signal is connected to the output of the amplitude demodulator, and the output to the input of the scaling amplifier, the output of which is connected to the second input of the adaptive amplitude limiter, the output of which is connected to the input of the bandpass filter, and at the first th input adaptive amplitude limiter input signal.