KR900007846Y1 - Circuit to supply tone - Google Patents

Abstract

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Description

Supply circuit using single tone source

1 is a conventional main supply circuit diagram.

2 is a block diagram according to the present invention.

3 is a detailed circuit diagram of the beep generator 100 of FIG. 2 according to the present invention.

* Explanation of symbols for main parts of the drawings

100: signal generator 200: DTMF receiver

300: currency circuit INF: interface circuit

CPU: Central Processing Unit ST1-STn: Subscriber

R1-R11: resistor D1-D2: diode

C1- C4: Capacitor OP1-OP6: Operational Amplifier

VR1: Variable resistor

The present invention relates to a tone supply circuit of a private exchange and a keyphone system, and more particularly to a tone supply circuit using a single tone source when using a tone receiver.

In general, the tone generation in a small private exchange or a keyphone system is to generate and supply eight kinds of tone and dial pulses used in the system.

FIG. 1 is a conventional tone supply circuit diagram. When a tone generator TG generates a predetermined signal, the mixer mixes and generates a composite sound. At this time, when the central processing unit (CPU) outputs the control signal of the data bus, the complex sound received from the mixer (Mix) is controlled by the tone cadence control circuit (TCC) to input the tone cadence to the tone jitter selection circuit (TIC), Since the tone jitter is controlled by the output control signal of the central processing unit (CPU), the input tone control signal, which is an input signal, is buffered in the buffer BUF and supplied to each network. As mentioned above, there is no problem in tone supply, but when the system is complex and the unit is trying to unify the tone source, it is not possible to perform digit sensing smoothly when the subscriber is an MFC phone. Dialtones or tones were mixed with other subscribers in the call, resulting in a disruption.

Accordingly, an object of the present invention is to provide a circuit capable of eliminating digit sensing and cross talk of multiple subscribers while using the tone source itself as a single tone source in a system that will not use dual tones.

Another object of the present invention is to provide a circuit that can increase the reliability of the system.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram according to the present invention, which includes a central processing unit (CPU) for controlling circuit driving and call progress, control signal output and diagnosis, and maintenance for port state check (loop, ring, digit) and call path formation. ), A tone generator 100 for supplying a single tone source, a DTMF receiver 200 for converting a DTMF signal into binary in case of MFC reception, and outputting the binary signal to the CPU, and a telephone line of a telephone. Forming a cross-point integrated circuit and a channel circuit 300 composed of a jitter and a port, a subscriber (ST1-STn) connected to a port of the telephone circuit 300, and the central circuit path 300 Receives a control signal from the processing unit (CPU), transmits a signal to open and close a designated crosspoint, and interfaces to input to the central processing unit (CPU) as a binary DTMF dial signal from the DTMF receiver 200. It is composed.

It turns out that the configuration circuit is a known configuration and the tone generating circuit 100 is to solve the conventional problems with a single tone source generating circuit of the present invention.

3 is a detailed circuit diagram of the beeper circuit 100 of FIG. 2 according to the present invention, in which R1-R11 is a resistor, D1-D2 is a diode, C1-C4 is a capacitor, OP1-OP6 is an operational amplifier, and VR1 is variable. The portion consisting of resistors R1-R4, diodes D1-D2, variable resistors VR1 and operational amplifiers OP1 is the one-bridge oscillator 10, resistors R5-R6, and capacitors C3. ), A portion composed of the operational amplifier OP2 is the amplification unit 20, and a portion composed of the resistors R7-R9, the capacitor C4, and the operational amplifier OP2 is the attenuation unit 30, and the operational amplifier ( The first buffer unit 50 buffers the output of the OP3) from the operational amplifier OP6 and inputs it to the tone stop terminal TJ, and the output of the associative amplifier CO2 is buffered by the associative amplifiers OP4-OP5. The portion configured to be input to the dial tone stages DT0-DT1 is the second buffer portion 40.

Therefore, if a specific embodiment of the present invention is described in detail with reference to Figs. 2 and 3, the central processing unit (CPU) listens to the dial tone when one of the MFC extension subscribers (ST1-STn) hooks and dials. The port of the call circuit 300 is checked to attach the tone receiver jitter and the dial tone jitter connected to the DTMF receiver 200 of the call circuit 300 together. At this time, the dual tone corresponding to the digit dialed by the station subscriber is inputted to the DTMF receiver 200, converted into a binary number by the DTMF receiver 200, and inputted to the central processing unit (CPU) through the interface circuit (INF). Will be detected.

In this case, since the dial tone jitter and the tone receiver jitter are held together at the port of the call circuit 300, the signal should not be input to the tone jitter so that the “high” impedance must be applied. The voice signal being talked out should be pulled out by the tone setter so that other subscribers cannot hear it.

For this purpose, when a predetermined signal is oscillated by the operational amplifier OP1, the resistors R1-R4, the capacitors C1-C2, and the diodes D1-D2, a predetermined signal is generated and the resistors R5 and R6 are calculated. Amplified by amplifier OP2, differentially amplified by resistors R7, R8, operational amplifiers OP3, capacitor C4, and resistor R9, and attenuating the signal, each of which is an operational amplifier OP4-OP6. ) And the output side of the operational amplifier (OP4-OP5) becomes the "low" impedance, so that the tone signal is heard through the subscriber (ST1-STn) port of the second channel circuit circuit 300, while the continuous amplifier (OP6) Since the attenuation output of the power amplifier is applied to the tone jitter of the circuit circuit 300, the output side of the operational amplifier OP6 has a "low" impedance so that the voice signal of each subscriber ST1-STn is not heard by the other subscriber. It will fall towards the tone stop.

In other words, the tone supply output side of the tone filter is a sink source.

As described above, when supplying a single phone or a small private exchange singleton, the tone supply side has a "low" impedance and the digit or voice signal side has a "high" impedance, so that the digit recognition is accurate and the crosstalk of the voice signal is eliminated. There is this.

Claims (1)

In a key-phone system or a private-switch tone supply circuit having an oscillator 10, an attenuation unit for amplifying the output of the oscillator 10 and an attenuation for attenuating the output of the oscillator 10 compared with a reference level. The unit 30 and the tone supply signal of the amplifying unit 20 are buffered to supply a dial tone so that the output has a "low" impedance and a "high" impedance to the MFC on the subscriber side to prevent crosstalk. Tone supply circuit using a single tone source, characterized in that consisting of a first buffer unit (50).