SU1570031A1 - Voice frequency receiver - Google Patents

Abstract

The invention relates to telecommunications and can be used in automatic long-distance communication systems. The purpose of the invention is to improve noise immunity and enhance functionality. The tone call receiver contains a matching unit 1, a shaper 2 rectangular pulses, a shaper 3 trigger pulses, a generator of 5 clock pulses, the first 6 and second 11 counters, a decoder 7, a trigger 8, the first 9 and the second 10 elements And, the execution unit 12, the latch 15 receiving a call. Improving noise immunity is achieved by eliminating false positives, for which a 4 delay block is introduced. Expansion of functionality is achieved by providing reception at M + 1 frequencies, for which M additional call receiving clamps are introduced. 1 hp f-ly, 2 ill.

Description

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The invention relates to telecommunications and can be used in systems of automatic long-distance communication and as well as in systems of tele-signaling and telecontrol.

The purpose of the invention is to increase the optical stability by eliminating false alarms and extending the functionality by providing reception on t + frequencies.

FIG. 1 shows a block diagram of a tone call receiver for the case of FIG. 2 — timing diagrams of a tone call receiver,

The tone call receiver contains matching unit 1, shaper 2, square pulses, shaper 3 trigger pulses “block 4 delays, generator 5 clock pulses, first counter 6, decoder 7, trigger 8, first element And 9, second element And 10 , the second counter 11, the Executive unit 12, the first output 3 of the decoder 7, the second output 14 of the decoder 7, the latch 15 receiving output.

The tone call receiver works as follows

From the communication channel, the tone frequency signal (fig. 2a) is fed to the input of matching unit 1. Further, the tone frequency signal passes through the shaper of 2 rectangular pulses and is fed to the shaper of 3 trigger pulses. At the output of the driver 3, a pulse sequence is formed with a sequence of short pulses (Fig. 26) with an input signal following frequency (one pulse per period). At the output of block 4 delay there is the same sequence (figv) of short pulses, but shifted by the delay time. The delay time Ј% of block 4 must be much less than the period T & input,

nala b "Ta tg and less period

L js t

V e

at

clock pulses. The pulses at the output of the driver 3 of the trigger pulses and at the output of the block 4 do not overlap (Fig. 26c).

The signal from the output of the generator 5 clock pulses (Fig "2d) enters the counting input of the counter 6 outputs of which-5

five

0

0

five

0

five

0

five

They are connected to the inputs of the decoder 7. Counter 6 operates continuously, dropping to zero from the output of block 4.

The signal at the output 14 of the decoder 7 (Fig. 2d) appears through the interval

time t, -, where Р „- frequency

FgB

upper boundary of the call reception area. This signal arrives at the S-input of the trigger 8 and sets it to position 1, allowing the element 9 to work.

The signal at output 13 of the decoder

7 (Fig. 2e) appears at interval

time t --- where F is the frequency

m

lower boundary of the call reception area. This signal arrives at the R-input of the trigger 8 and sets it to the O position, allowing the element And 10 to work.

The pulses from the output of element 9 are fed to the counting input of counter 1I, where they are counted. The pulses from the output of the element 10 set the counter 11 to the initial state. The capacity of the counter 1I determines the call signal selection time. The signal from the output of the counter 11 includes the Executive unit 12, signaling the fact of receiving the call.

Consider the operation of the receiver tonal call in different frequency zones.

In zone J (FIG. 2), the frequency of the received signal is less than the lower cut-off frequency. The period of the received pulse is maximum, the signals have time to appear both at the output 14 and at the output 13 of the decoder 7 (fig.2d, e, zone I), the trigger 8 is set to position 1, and then to the position o (fig.2g).

8 the beginning of the next period of the input frequency pulse from the output of the imaging unit 3 triggering pulses finds the prepared element And 10, the signal

from the output of which (FIG. 2i) sets the initial status of the checker 11, the fact that the call frequency does not occur does not occur.

In zone II, the frequency of the input signal is greater than the lower limit frequency of the reception area, but less than the upper limit frequency of the reception area. During the input signal period, only the signal from the output 14 of the decoder 7 has time to appear, it sets the trigger 8 to the state l and prepares the operation

element 9. At the beginning of the next period of the input frequency, the signal from the output of the driver 3 trigger pulses, the prepared element 9 (FIG. 2) passes to the counting input of the counter 11 “Through the delay time, the signal from the output of the delay block 4 sets the trigger 8 and the counter 6 to the initial state, and a new analysis cycle is started. When filling the counter 11, the executive unit 12 is activated, fixing the fact of receiving the call,

In zone III, the frequency of the input signal is greater than the upper limit frequency of the reception zone, the period of the input frequency is minimal. During the period of the input frequency, the signal neither at output 14 nor at output 13 of the decoder 7 has time to appear, so trigger 8 remains with state O. The element AND 10 is prepared. The incoming signal from the driver 3 triggers This element 10 (Fig. 2i) sets the counter 11 to the initial state. There is no call frequency recognition.

Thus, if there is even one period of the input signal with a frequency less than the lower boundary frequency of the reception area (Fig. 2, zone I) or with a frequency greater than the upper boundary of the reception zone (Fig. 2, zone III), the counter 11 is set to the original condition.

Consequently, the execution unit 12 is triggered only if the additional time K of the periods of the input section that are in the call reception area is received (K is the capacity of the counter I). Obviously, if the frequency of the input signal is unstable, a false positive does not occur.

As the counter 6 is reset only at the beginning of each period (before the next measurement cycle), the matching unit 1, the shaper 2 rectangular pulses, the shaper 3 trigger pulses, the delay block 4, the generator 5 clock pulses, the counter 6 and the decoder 7 can be used for the selection of several call frequencies, having for each selectable frequency only an individual fixed 15 call reception, (a set of trigger 8, elements 9 and 10, counter II

and the executive unit 12), and arrange additional outputs of the decoder 7.

Claims (2)

1. A tone call receiver containing a matching unit whose input is the input of the tone call receiver, and the output through the square pulse shaper is connected to the input of the trigger pulse generator, clock generator, the first counter, n outputs of which are connected respectively to the decoder inputs, the first the output of which is connected to the first input of the call receiving clamp, which contains a series-connected trigger and the first element II, which are connected in series to the second counter and is An additional unit and a second element AND, the second input of which is connected to the second input of the first element AND, and is the second input of the call receiving clamp, the first and third inputs of which are respectively the first and second trigger inputs, characterized in that, in order to improve noise immunity, eliminate false positives, a delay block is inserted, the input of which is connected to the output of the trigger pulse generator and the second input of the call receiving latch and the output is connected to the fourth input of the call receiving latch and the first input The first counter, the second input of which is connected to the output of the clock pulse generator, while the second output of the decoder is connected to the third input of the call receiving clamp, the fourth input of which is the third trigger input, the second output of which is connected to the first input of the second And element, the output of which is connected to the first input of the second counter, the second input of which is connected to the output of the first element And, 2. The receiver is pop-1, which differs from the fact that, in order to extend the functionality by providing reception at t + 1 frequencies, m additional call receiving clamps are introduced, the first and third inputs of which are connected respectively to m first additional and ha to the second additional outputs of the decoder, and the second and fourth inputs m of the additional call handlers are connected respectively to the input and output of the delay unit