SU450381A1 - Tone Receiver - Google Patents

Description

one

The invention relates to the field of automatic telephone communication and is intended to receive current-frequency pulses of the frequency and convert them into signals suitable for controlling switching equipment.

However, the known devices exclude the possibility of receiving tonal dialing signals, in addition, the known devices have a rather complicated scheme for performing frequency selection.

In order to receive the tone dialing signals in the proposed receiver, the common-mode output of the amplifier-amplifier is connected to the one-vibrator input through the comparison circuit, and the anti-phase output of the amplifier-amplifier is connected to the input of the electronic key, to the control input of which the second output of the comparison circuit is connected; In addition, the comparison circuit is made of two transistors, the base and the emitter of one of which are respectively connected to the emitter and the base of the other transistor, and the collectors of these transistors are connected to the power sources via a load resistor.

FIG. 1 shows the block diagram of the proposed tone receiver; in fig.

2- the same, schematic diagram; in fig.

3- diagrams of the receiver.

The proposed receiver of tone signals contains matching device 1, amplifier-shaper 2, comparison circuit 3, single-vibrator 4, electronic switch 5, actuator 6, diode 7, transistor 8, resistor 9, transistors 10, 11 and 12, load resistor 13, capacitor 15, transistors 16 and 17, resistors 18 and 19, diode 20, transistor 21.

The receiver works as follows.

When the signal frequency in the amplifier-shaper 2 arrives at the receiver's input, a sequence of square negative pulses is formed using positive half-cycles of the sinusoidal current, the leading edges of which through the comparison circuit 3 trigger the one-shot 4 in time with the pulses coming from the amplifier-shaper 2.

At the signal frequency, the duration of the negative pulse of the one-shot 4 is chosen equal to the duration of the output pulse of the amplifier-former 2. Thus, at the inputs of the comparison circuit

3, a sequence of negative pulses of equal duration arrives at the output of amplifier 2 and one-shot 4, as a result of which the output voltage at the output of the comparison circuit 3 is zero. Key

5, the negative half-periods of the sinusoidal current, coming from the Second, the output of amplifier 2, freely pass to the input of the actuator 6, which is triggered.

When the talker currents with frequencies other than signal currents enter the receiver input, the inputs of the comparison circuit 3 from the outputs of the amplifier-former 2 and the one-oscillator 4 receive pulses of different duration, as a result of which the output of the comparison circuit 3 appears ; in this case, the actuator 6 cannot work.

A signal frequency current arriving at the receiver input (Fig. 2) is fed through a matching device 1 to the amplifier amplifier 2 input. Amplitude-limited positive half-cycles of the signal frequency current through the diode 7 enter the base of the normally open transistor 8 and close it.

As a result, in the collector circuit of this transistor, a sequence of negative pulses is formed on the resistor 9 with durations equal to the half-cycle duration of the input sinusoidal current.

Between the collectors of transistors 8 (amplifier-maker 2) and transistor 10 (one-shot 4) a comparison circuit is included, made on transistors 11 and 12, the base and emitter of which are connected to each other, and the collectors of these transistors are connected and connected to a power source through a resistor 13 load, parallel to which the capacitor 14 is turned on

To the resistor 13 through the capacitor 15 is connected to the base of a normally closed transistor 16.

The transistor 17 is open by the negative potential of the power source supplied to its base through the resistor 18.

The leading edges of the pulses of the formed sequence through the comparison circuit 3 trigger the one-shot 4 in time with the pulses coming from the output of the amplifier forming unit 2. At the signal frequency, the duration of the negative pulse of the single-setting 4 is chosen equal to the duration of the output pulse of setting amplifier 2.

Thus, the output of the comparison circuit 3 from both the collector of the transistor 8 and the collector of the transistor 10 of the one-shot 4 simultaneously receives a sequence of negative pulses of equal duration. Therefore, the same potentials are applied to the bases and emitters of the transistors 11 and 12, so these transistors are closed, and the variable component on the collectors of the transistors 11 and 12 is zero, which can be seen from the diagram (Fig. 3), in which f / i living on the collector of the transistor 8 of the amplifier-former 2; f / 2 is the voltage across the collector of the transistor 10 of the single-oscillator 4; / 7g is the voltage across the load resistance 13. The transistor 16 is closed in this case and the transistor 17 is open, therefore the negative half-cycles of the signal frequency current flowing through the resistor 19 and the diode 20 to the base of the transistor, 21 open it, and the relay connected to the collector this transistor is triggered.

If the receiver receives currents with frequencies below the signal, then the pulse duration Ui (Fig. 3.6) entering the comparison circuit 3 from the output of transistor 8 is longer than the pulse width Uz entering the comparison circuit 3 from the collector of transistor 10 of the single-oscillator 4, in this case, at the instants of time ti, the transistor 11 opens along the circuit: minus - resistor 9 - base of transistor 11-emitter - plus through the open transistor 10.

In the collector circuit on the resistor 13 in TC, there are positive pulses Out through open transistors 10 and 11 (Fig. 3.6).

In the event that currents with frequencies higher than the signal duration of the pulses Ui arrive at the receiver input, amplifier 2 (Fig. 3.0) has a smaller output

the duration of the pulses U of the one-shot 4, while at times 4 (Fig. 3.8) the transistor 12 is opened through the open transistor 8, and the pulses of a positive polarity Us are also on the resistor 13.

Thus, when currents with frequencies both lower as compared with signal and frequencies higher than signal are received, pulses of positive polarity appear at the output of the comparison circuit.

The variable component of these pulses through the capacitor 15 is supplied to the base of the transistor 16, which is opened. When opening the transistor 16, the transistor 17 is closed, and since it is connected in series with the actuating element, the operation of the latter is excluded.

With the help of a capacitor 14 connected in parallel to the resistor 13, the required working bandwidth of the receiver frequency is set.

Subject invention

Claims (2)

1. Receiver tones containing a matching device connected to the amplifier-driver, one-shot, An electronic key connected to an actuator, characterized in that, in order to ensure reception of the tone-call signals and the tone dialing, the common-mode output of the amplifier-former through the comparison circuit is connected to the input of the one-shot, and the anti-phase output of the amplifier-former is connected to the input of the electronic switch, to the control input of which the second output of the comparison circuit is connected. 2. The tone receiver of claim 1, wherein the comparison circuit is implemented on two transistors, the base and the emitter of one of which are respectively connected to the emitter and the base of the other transistor, and the collectors of these transistors are connected to the power source via a load resistor. Fig, 1 (I and, U