SU1508241A1 - Device for differentiating between frequency signals - Google Patents

Abstract

The invention relates to telemechanical devices for transmitting information via communication channels. The purpose of the invention is to increase the reliability of various frequency signals. The device contains a band-pass filter 1, a signal channel filter 2, a reference channel filter 3, a pulse shaper 4, a shaper of information pulses 5, a shaper of symbols 6, four decoders 7, 8, 9 and 10, a pulse generator 11, the HE element 12, two keys 13 and 14, differentiating element 15, one-shot 16, element OR 17, three counters 18, 19 and 20, subtractor 21 and register 22. Tab. 1, 1 Il.

Description

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The invention relates to the field of telemechanical devices for transmitting digital information via communication channels 1 and can be used to construct a signal to measure a negative pulse AND and a positive pulse T - 1 (T - ne {). Iodine filters 2 and 3 make it possible to repeatedly produce the interval of the duration of sending the difference measurement,

telemechanical devices for transmitting information in control systems with digital computers.

The purpose of the invention is to increase the reliability of distinguishing frequency signals.

The drawing shows the functional diagram of the device.

The device contains a bandpass amplifier 1, a filter 2, a signal channel, a filter 3 of the reference channel, a pulse shaper 4, a pulse of 5 information pulses, a shaper of 6 symbols, four decoder 7-10, a AND pulse generator, an element of HE 12, two keys 13 and 14, differentiating element 15, one-shot 16, element OR 17, three counters 18-20, subtractor 21 and a register 22.

The device works in the following manner.

The sending voltage, consisting of 15 periods of the signal frequency, goes from the communication channel to the input of the band amplifier 1. The passage through the filter 2 of the signal channel, the voltage of this frequency is shifted by 10

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parcels of the parcel) after counting 8-15 frequency periods} by means of the decoder 8, after distinguishing the signal, set counter O to O.

The decoding of the state of the triggers of this counter is performed by the decoder 9, the voltage at the first output of which corresponds to fixation of the 8th period, on the second 9, on the third Yu, the fourth 11, and from 12th to the eighth - 15 periods.

The levels corresponding to fixed period numbers at the output of the decoder 9 are fed to the input of the imaging unit 5 of the information pulse. This shaper receives information pulses from the subtractor 21. From the output of the imaging unit 5, the information time interval of negative polarity Sf goes to three paths: the measurement path of the negative information time interval formed by the first key 13, the generator 11 of filling pulses, the counter 18 and decoder T tract measurement measurement time intervals formed by

The levels corresponding to the fixed period numbers at the output of the decoder 9, are fed to the input of the forwarder 5 information pulse. This shaper receives information pulses from a subtractor 21. From the output of the imaging unit 5, the information time interval of the negative polarity Sf goes to three paths: the measurement path of the negative information time interval formed by the first key 13, the generator 11 of filling pulses, and a counter 18 and a decoder T for measuring the test time intervals formed by

which angle is if and through filter 3

reference channel - at an angle Lf. You are 35 elements NOT 12, the second key is 14,

During the subtractor 21, the phase difference is represented by a time interval whose duration t is proportional to the phase difference difference% -g. When measuring the phase shift of two sinusoidal voltages, the characteristic moments of a sinusoidal voltage transfer through 40

the element OR 17, the counter 20, the decoder 10; installation path in О counters 20 and 18, formed by differentiating element 15 and single-vibrator 16.

In the measurement path of the negative time interval t from the dioD output

The worldviewer 5 receives this interval at the second input of the key 13. The first input of the switch 13 receives pulses from the pulse filling generator 1 (frequency 1 MHz). From the exit key. 13 pulses arrive at the counting input of the counter 18, which will be fixed

left levels. The phase shift is converted to a time interval, and to obtain a numeric equivalent, this time interval is converted to a digital code.

.,, „„ „„ „„ -Iin a number that is numeric. From the output of amplifier 1, this is also the case.

The pulse enters the pulse maker 4 pulses and pulses are formed from the sending periods, which are counted under counter 19. The counter performs the following functions, and the name of the decoder 7 will produce levels for information inputs

equivalent information interval proportional to the difference in phase shifts.

Depending on the number of the number

but: determines the time of measurement of the | nasti phases of the growth increment; accurate amplitude of the output signal

Former 6 characters. These levels are indicative of transmitted octal characters.

 give a signal to measure negative pulses And and positive pulses T - 1 (T - ne {); iodine filters 2 and 3 allow to repeatedly make a difference measurement on the interval of

parcels of the parcel) after counting 8-15 frequency periods} by means of the decoder 8, after distinguishing the signal, set counter O to O.

The decoding of the state of the triggers of this counter is performed by the decoder 9, the voltage at the first output of which corresponds to fixation of the 8th period, on the second 9, on the third Yu, the fourth 11, and from 12th to the eighth - 15 periods.

The levels corresponding to fixed period numbers at the output of the decoder 9 are fed to the input of the imaging unit 5 of the information pulse. This shaper receives information pulses from the subtractor 21. From the output of the imaging unit 5, the information time interval of negative polarity Sf goes to three paths: the measurement path of the negative information time interval formed by the first key 13, the generator 11 of filling pulses, the counter 18 and decoder T tract measurement measurement time intervals formed by

element NOT 12, the second key 14,

the element OR 17, the counter 20, the decoder 10; installation path in О counters 20 and 18, formed by differentiating element 15 and single-vibrator 16.

In the measurement path of the negative time interval t from the dioD output of world 5, this interval goes to the second input of the key 13. The first input of the key 13 receives pulses from the pulse filling generator 1 (frequency 1 MHz). From the exit key. 13 pulses arrive at the counting input of the counter 18, which will be fixed

is a number that is numeric

The frequency decoder 7 is equivalent to an information interval proportional to the difference in phase shifts.

Depending on the number of the number

Former 6 characters. These levels are indicative of transmitted octal characters.

in the measurement path of the test Positive time interval i from the output of the imaging unit 5, this interval goes to the element NOT 12 and then to the first input of the key 14, The second input of the key 14 receives pulses from the generator 11, From the output of the key 14 the checking pulses go to the second input of the element OR 17, At 10, its first input from the key 13 is received by filling pulses. From the output of the element OR 17, the filling pulses h of the check come to the count input B of the communication channel. The frequency burst, consisting of 15 periods of the signal frequency of 2830 Hz, comes from the communication channel to the input of the bandpass amplifier 1. The signal amplified to the desired level is fed to the input of filters 2 and 3 of the signal and reference channels. When passing through the filter 2, the voltage of the EJO frequency is shifted by the angle if, 350 °, and through the filter 3 by the angle tpj 222, at the output of the subtractor 21, the phase difference c; is represented by the time interval, the duration

20, Counters 20 and 18 the simultaneity of which is proportional to 350 times

but counting the filling pulses of the negative information time interval, the number of which is proportional to the number of the frequency premise, after which the decoder 10 provides permissive levels for the control inputs of the driver 6 characters.

The positive part of the period with duration i, having passed through the element NOT 12, enters the first input of the key 14 and the number of filling pulses, proportional to the duration G, enters through the second input of the element OR 17 to the counting input of the counter 20, K having the filling pulses proportional to i ),, pulses are added, the number of which is proportional to the positive part of f / j. Thus, the counter 20 will record the number of pulses proportional to 1, - f, t, e, period duration, In a narrow range of distinguishable frequency signals (2700., 3000 Hz), the period duration is (350tI6) µs. When a certain number of pulses (350 + 16) is reached, the decoder 10 has the resolving Levels to the control inputs of the former 6 characters, with which the received symbol is written to the output register 22,

When distinguishing 8 frequencies in the range of 270: 0 ,,, 3000 Hz frequencies, the corresponding octal symbols, binary symbols, phase shift differences, proportional to them time intervals i, and I j, the number of counting pulses in counters 20 and 18 are distributed as follows way (see table),

Consider the example of distinguishing the frequency fg 2830 Hz (octal symbol 3) of the device in the absence of impulse noise and interruption 6

in the communication channel. The frequency burst, consisting of 15 periods of the signal frequency of 2830 Hz, is fed from the communication channel to the input of the bandpass amplifier 1. The signal amplified to the desired level is fed to the input of filters 2 and 3 of the signal and reference channels. When passing through the filter 2, the voltage of the EJO frequency is shifted by the angle if, 350 °, and through the filter 3 by the angle tpj 222, at the output of the subtractor 21, the phase difference c; is represented by a time interval whose duration is proportional to

of phase shifts cf, - “222 ° 128. At frequencies of 2700.,. 3000 Hz period duration is in the range of 370 .., 333 μs. Therefore, we can assume that the shift by 1 ° corresponds to the duration

 μs, and then the phase difference / zs 128 ° corresponds to 128 m§ ,. With a filling frequency of I MHz and 5 pulses. Information interval

corresponding to the 8th frequency frequency period, the duration of which is proportional to the difference in phase shifts, goes to the informational

0 input shaper 5 information pulses. The control inputs of the imaging unit 5 from the decoder 9 receive pulses at the moment of fixing by the counter 19 8-15 sending periods. From the output of the imaging device 5 information pulses, the information interval of negative polarity of 128 µs goes to the second input of the key 13 and allows the filling of the pulses from the generator 11 of filling pulses to the counting input of the counter 18 and the first input of the OR element 17. Depending on the duration of the information (control interval) the counting input of the counters 20 and 18 will receive the number of impulses L, proportional to its duration, t. e. 128. Through the decoder 7, the number 128 is decrypted and the shaper of 6 characters receives the levels used to write octal 3 to the output register 22, i.e. 011, Write to the output register 22 characters 3 will be carried out upon arrival at the control inputs of the former 6 permitting levels from the decoder 10, and this will take place in the following manner.

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From the output of the information pulse shaper 5, the test interval of positive polarity with a duration of 222 MKS goes to the HE element 12, where it is inverted and fed to the first input of the key 14, which allows the passage of filling pulses to the second input of the OR element 17 and then to the counting input 20. The counting input of counter 20 will receive the number of pulses proportional to its duration, i.e. 222. But the counter 20 has already fixed the number 128, Therefore, the counter 20 will have the sum of pulses 128 + 222 350. The presence of the number 350 is decrypted by the decoder jI 10 as a reliable reception and permitting levels are received at the control inputs of the imager 6, as a result Character 3 (011) is written to the output register 22. A similar procedure takes place when the decoder decodes 9 remaining periods, i.e. 9-15. In the absence of interference on each new dimension, beginning with, 9 and ending with the 15th period, there is confirmation of the entry in the output register 22 octal characters. 3 (011). In the 15 period, the trailing edge of the positive test pulse by means of the differentiating element 15 and the one-shot 16 are installed in O counters 18 and 20.

Let us consider, by the example of frequency discrimination, 2990 Hz (octal symbol 7), the operation of the device in the presence of impulse noise, interruptions in the communication channel. Assuming that interference is affected, the intervals corresponding to -10, 11 periods (between them, i.e., the interference captures both periods) and 13 and 15 periods of the frequency burst. In this case, the durations of informational C and test intervals t), j, obtained during xenation of 10,11,13,15 periods, will not be proportional to the nominal difference of phase shifts (for symbol 7 it is 304) and, therefore, in the counter 18 will not write the number 304, but other numbers corresponding to other characters. Then, in the counter 20, no other word 350 will be written, but any other. In this case, the decoder W does not give / will allow the control levels for the driver of the 6 characters and in the output register 22 for the period

dah 10,11 and 13,15 character entries will not occur. For periods 8,9,12, 14, the entry in the counters 20 and 18 pulses will occur normally, i.e. 350 pulses are recorded in counter 20, and 304 pulses are counted in counter 18. Make sure that the counters 20 and 18 are correctly decoded and the octal number 7 (111) is written to the output register 22.

Claims (1)

Formula of inventions A device for distinguishing frequency signals, comprising a band-pass amplifier, whose input is an input of the device; which are connected to the first and second inputs by subtracting the bodies, respectively, a filling pulse generator, the output of which is connected to the first input of the first key, the output of which is connected to the counting input of the first counter, the outputs of which are connected to the inputs of the first decoder, a register, differentiating element, characterized in that , in order to increase the reliability of distinguishing frequency signals, introducing a pulse shaper, two counters, a three-, a decoder, an element NOT, a second key element OR, a one-shot, a driver information pulses and a shaper of characters, the output of a bandpass amplifier is connected via a pulse shaper to the counting input of the second counter, the outputs of the first group of outputs of which are connected to the inputs of the second decoder, the output of which is connected to the Reset input of the second counter, the outputs of the second group of outputs of which are connected to the inputs of the third decoder, the outputs of which are connected to the control inputs of the information pulse generator, the output of the subtractor is connected to the information input of the information generator ion pulses, the output of which is connected to the second input of the first key, through the NO element to the first input of the second key and through a series-connected differentiation element and a one-shot to the inputs Reset the first and third counters, the output of the first key is connected to the first input of the element OR, the output of the filling pulse generator is connected to the second input of the second key, the output of which is connected to the second input of the OR element, the output of which is connected to the counting input of the third counter, the outputs of which are connected to the inputs of the fourth decoder, the outputs of the first and fourth decoders are connected to information control inputs a symbol maker, respectively, the outputs of which are connected to the inputs of the register, the outputs of which are the outputs of the device.