SU866779A2 - Voice frequency call receiver - Google Patents

Description

(54) CRIMINAL RECEIVER

I

The invention relates to telecommunications, in particular, to a technique for receiving call signals and dialing in long-distance telephone communication and switching systems, and can be applied in automation systems and in measurement technology.

According to the main author. St. No. 69О655 is known for a tone call receiver (PTV), which contains a zero detector, a zero transition counter, a clock generator, a clock counter, AND and OR elements, a trngg, a frequency divider, two NAND units, a time counter, and a counter of time. The output of the communication channel is connected to the input of the amplifier, the output of which is connected to a series-connected amplitude limiter, a frequency divider and a zero detector, one of the outputs of the latter is connected to the input of the first trigger, and the second output to the input of the element OR and one of the inputs of the element And, the output of the first trigger is connected to one of the clock counter inputs, the second input of which is connected to the output of the clock generator, the output of the OR element is connected to the second input of the first trigger and to the other one the second trigger, the outputs of the clock counter are connected to the inputs of two NAND, the output of one of which is connected to the input of the second trigger, and the output of the second AE element is connected to the second input of 14LE, the output of the second trigger is psed to the second the input element And

15 whose output is connected to one of the inputs of the time interval counter and the third trigger, the last timer output is connected to one of the time counter inputs, the other input of which is connected to the clock pulse generator output, and the time counter output with the second inputs of the third trigger and the time counter intervals. to the output of which the executive is connected. However, this device is not sufficiently high noise immunity. The purpose of the invention is to observe the protection of the device. The goal is achieved by the fact that in a tone dialing terminal that contains a null detector, a clock generator, a clock counter, AND and OR elements, triggers, a frequency divider, two NAND units, a time counter, and a time counter, the output the communication channel is connected to the input of the amplifier, the output of which is connected to the series-connected amplitude, limiter, frequency divider and zero detector, one of the outputs of the latter is connected to the input of the first trigger, and the second output is connected to the input of the OR element and from the inputs of the element I, the output of the first trigger is connected to one of the inputs of the counter of such pulses, the second input is connected to the output of the clock generator, the output of the element OR is connected to the second input of the first trigger and to the other input of the second trigger, outputs of the counter of clock pulses are connected with the inputs of two NAND elements, the output of one of which is connected to. the second trigger is output, and the output of the second element is NOT connected to the second input of the OR element, the output of the second trigger is connected to the second input of the AND element, the output of which is connected to one of the terminals of the time interval counter and the third trigger, the output of the latter is connected to one of inputs of the time counter, the other input of which is connected to the output of the clock pulse generator, and the output of the time counter with the second inputs of the third trigger and the counter of time intervals, to the output of which the actuating node is connected, are entered t NOT, two additional elements AND, as well as the fourth and fifth triggers, while the output of the amplitude limiter is connected to the input of the element NOT and to the first input of the first additional element AND, the output of which is connected to the first inputs of the fourth and fifth triggers and to the other input is the split frequency, the output of which is connected to the K.O. the second input of the fourth trigger. 94 the element output is NOT connected to the first input of the second additional element I, the output of which is connected to the second input of the fifth trigger, while the output of the fourth trigger is connected to the second input of the second additional element I, and the output of the fifth trigger is connected to the second input of the fifth additional element And, FIG. 1 is a structural electrical circuit of the device described; Fig. 2 shows timing diagrams for determining the call frequency at different frequency division factors. The device contains an amplifier 1, an amplitude limiter 2, a divider 3 frequencies, a NOT 4 element, a first additional element AND 5, a second additional element AND 6, a fourth and fifth trigger 7 and 8, a zero detector 9, the first trigger 10, element OR 11, a clock counter 12, a clock generator 13 pulses, two AND-NO elements 14,15, a second trigger 16, an AND element 17, a time interval counter 18, a third trigger 19, and a time counter 20. The tone call receiver works as follows. When a device arrives at a device input from a communication channel (for example, a call or dial tone), it is amplified by amplifier 1 and converted into square impulses using an amplitude limiter 2 (Fig. 2a) and simultaneously the input element is NOT 4, and one of the inputs of the first additional element is AND 5. The frequency divider 3 provides a statistical averaging of the incoming tones over a time interval whose duration is equal to I times the duration of the lkey period of the mentioned signals (figch 2 b, c, d, obtained at I -2,4,8). Due to this, the relative errors of fixing the fronts of the signals are reduced and thus the noise immunity of the device is increased. From the output of the divider 3 frequencies, rectangular pulses of the signal arrive at the input of the zero detector 9 and at the same time at one of the inputs of the fourth trigger 7. The impulse voltage through the element NOT 4 is applied to one of the inputs of the second additional element I 6, to the second input of which from the output of the fourth trigger 7 enters the locking potential. Since in this case the potential of the ban does not come to the second input of the divider of 3 frequencies, it functions in the normal press. From the trailing edge of the pulse (Fig. 2b, c, e) the fourth trigger Tis of its output is thrown, the unlocking potential is fed to the second additional element I 6, From the output of the last at the moment the element 6 of the permit pulse arrives at the first input (Fig. 2 a) a control potential is applied to one of the inputs of the fifth trigger 8, which is transferred and delivers the unlocking potential to the first input of the first additional element 5. When the second input of this element is a non-inverted pulse (Fig. 2a) from the output of the AND element 5 served the potential dropping the divider 3 frequencies to the zero state and transferring the fourth and fifth triggers 7 and 8 to the initial (zero) state. Due to this, the interval between two pulses from the output of the divider 3 orient frequencies AND 2j decreases and becomes equal to the period of the signal of the calling frequency (Fig. 2c, d, d, e). From one of the outputs of the zero-detector 9, the mark n of the front of the pulse (Fig. 2b, e) goes to the first {first entrance of the first trigger 10, which is thrown and removes the inhibitory potential from the input of the counter 12 clock pulses. The latter starts counting pulses from the generator output of 13 clock pulses, the frequency of which is many times higher than the frequency of the call tone signal and is, for example, 1 MHz (the higher this frequency, the higher the accuracy of the call period duration) . Counter 12 has two groups of outputs: one of them is connected to the input of element I-HE 14, which records the minimum permissible call signal duration (corresponds to the maximum permissible frequency of this signal) and the second to the element AND-HE 15, which fixes the maximum permissible duration call signal (corresponding to the minimum permissible frequency of this signal). The potential coming from the output of the element AND-14, is fed to one 96 of the inputs of the second trigger 16, which is transferred and supplies the resolving potential to the first input of the element 17. If the potential corresponds to the trailing edge of the pulse (Fig. 2b, g e), comes from the output of the null-detector 1 to the second input of the element AND 17 before the pulse from the output of the element AND-NOT 15 appears, then from the output of the element And 17 a pulse is given, the signal is received, whose frequency is within normalized limits. If the pulse from the output of the element AND –NE 15 is fed to the input of the element OR 11 until the input signal of the rear endcamp tag appears at the second input of this node, then the output of the element OR 11 is given a pulse to the second input of the second trigger 16, which is tilted condition. Due to this, the resolving potential is removed from the corresponding input of the element 17 and the possibility of passing this node of the trailing edge of the signal (Fig. 2 b, d, e) is eliminated by entering from the corresponding output of the zero detector 9. The x-pulse, which comes from the output of the element OR 11, the first trigger 10 is descended to the initial state. As a result of this, the recording potential jia receives one of the inputs of the counter 12 clock pulses, which returns to the initial (zero) state. Due to the foregoing, a high selectivity of the reception of a call signal is ensured by the period duration (frequency) and the operability of the device with a permissible variation in the length of the period (frequency) of the specified signal. The pulses passed through the element And 17, are fed to one of the inputs of the counter 18 time intervals and simultaneously to one of the inputs of the third trigger 19, which tilts and starts the time counter 20, the power of which is chosen so that for some fixed time TQ to receive a certain the number of periods of the signal. This ensures that the call device is protected from a certain duration of ommeh, which is identical to the introduction of

Slow-tone callbacks for triggering.

If during the TQ time, the 18 time interval counter detects a certain (selected) number of pulses, then from its output the potential is applied to the actuator, which operates and records the arrival of a call signal. If, during time Tg, the number of pulses recorded by the counter of 18 time intervals, NCHB beyond the allowable time, a pulse is emitted from the output of the timeclock 20, the tipping third trigger 19 of the counting circuit returns to its original state and resets to zero counter 18 time intervals. In this case, the actuator does not trigger.

Claims (1)

Invention Form Tonal Receiver on bus, № 690655, о tl and h and y98 Sch and with the fact that, in order to increase the noise immunity, a NOT element, two additional AND elements, as well as fourth and fifth triggers are introduced, while the output of the amplitude limiter is connected to the input of the HE element and to the input input of the first additional element And / / the output of which is connected to the second input of the fifth trigger, while the output of the fourth trigger is connected to the second input of the second additional element, and the output of the fifth trigger is connected to the second input of the first additional element I. Sources of information taken into account in the examination 1, Author's testimony of the USSR in application number 2531083.kl.N 04 / O9 Q 3 / O4. 1977, (prototype). JlJTJlJ 8 j J e J L L .. LriJnjnLJTJnJ lXLnja