KR830000364B1 - Voice discrimination circuit - Google Patents

Abstract

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Description

Voice discrimination circuit

1 is a block diagram of a speech discrimination circuit for an automatic telephone answering device according to the present invention.

2 is a waveform diagram for explaining the circuit operation of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speech discrimination circuit for an automatic telephone answering device, and more particularly to a speech discrimination circuit for operating a caller's message recording tape only when there is a voice from a caller.

The automatic telephone answering device is configured to transmit a message informing the caller of the absence by a bell signal and subsequently to record the message of the caller. Here, various methods have been conventionally used to set the time for recording the caller's message.

The oldest method is the so-called 'time-fixed' method, which is a method that is rarely used at this time because there is a drawback of the caller's message recording tape or the recording cannot be completed. It is a method of (VOICE ACTIVATION) that the caller's message, that is, while the voice is present, continues to record without suggesting a time, and if there is no voice for a certain time interval (for example, 10 seconds), all functions are restored to the standby state.

However, the switchboard connected to the automatic telephone answering device transmits an intermittent tone such as a busy-back tone or a continuous tone after the caller first hangs up the phone depending on the switchboard. In addition, the voice driving method has a drawback in that it is not possible to accurately distinguish the call tone and the dial tone from the voice. Various circuits have been devised so far in the speech discrimination circuit capable of distinguishing the speech from the mechanical sound, but the present invention makes speech discrimination based on the criterion of the regulation of the sound intermittent pattern and is much more advantageous than the conventional one in terms of reliability and price. The purpose is to provide a new concrete circuit.

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

In FIG.

Reference numeral 1 denotes an audio amplifier for amplifying a signal applied at an input terminal;

Number (2) is a Schmitt TT TRIGGER circuit for removing a signal below a certain level,

No. (3) indicates that when the negative signal, the output of the Schmitt trigger circuit (2) is not determined uniformly as a logic level HIGH or LOW LOW, so that the capacitor for DC suppression to make all of them low,

Numeral 4 denotes an inverter for phase inversion and waveform shaping.

The diodes 5, resistors 6, 7, and capacitor 8 constitute the first integrator 22, with a charging time of 12 ms, a discharge time of 2 ms, and detecting signal components of 100H2 or less.

Reference numerals 9 and 10 denote inverters for phase inversion. The diode 11, the resistor 12, and the capacitor 13 constitute the second integrator 24, and remove the signal having the instant charge and discharge time of 100 ms and the signal duration of 70 ms or less. Reference numeral 14 denotes an inverter for phase inversion.

점의 전압변화가 있을시만 카운터(19)에 리셋트(RESET)신호를 제공한다.The capacitor 15 and the resistor 16 constitute a differential circuit 24

The reset signal is provided to the counter 19 only when there is a voltage change of the point.

(17) is a synchronous 4-bit counter (SYNCHRONOUS 4bit COUNTER), and the pulse applied to the C (CLOCK) terminal when the ST (S YNCHRONUS RESET) terminal voltage is HIGH transitions from LOW to HIGH (hereinafter referred to as L → H). When 16 clock pulses are applied, it generates high output at TC (TERMINALCOUNT-OUTPUT) stage.

If the clock transition from L to H occurs while the SR input terminal voltage is LOW, the counter content of the counter 17 is reset. Commercially available ICs having this function include 74163 as TTL and 40 163 as CMOS, and CMOS 40163 is used in the circuit of the present invention. 18 is a square wave oscillator for providing a reference time.

Reference numeral 19 denotes a counter configured to divide the signal of the oscillator 18 as a counter so as to output a HIGH output to the output terminal Qn after a predetermined time, for example, 10 seconds later. Reference numeral 20 denotes a logic gate (hereinafter referred to as an OR gate) that outputs to the output terminal OUT when there is an output of either the counters 17 and 19.

Next, the operation of the embodiment circuit having the configuration as described above will be described.

When the bell signal from the telephone line arrives, a predetermined message is transmitted, followed by a recording circuit for recording the message from the caller. This is when the HIGH signal is displayed at the output terminal (OTU) of the OR gate 20 of FIG. Maintained until. It stops the recording circuit of the caller message of the signal at the output terminal OUT.

The caller's voice signal is a waveform with irregular amplitude changes as shown in Fig. 2a, and the ring tone sound generated from the switchboard is periodic in tone duration and interval as shown in Fig. 3a. The amplitude is also characterized by a constant.

First, a circuit operation when an audio signal is applied will be described with reference to the waveform of FIG. 2 with reference to FIG. 1 as a circuit block diagram.

The signal applied through the telephone line is amplified in a form superimposed on the DC + 4V in the amplifier (1). This is to change the signal below a certain amplitude in order to further increase the non-uniformity of the tone interval and duration characteristic of the voice signal in the shoe and trigger circuit 2 of the next pipe.

점의 파형은 제2도b 그림과 같게 된다.The Schmitt trigger (2) removes the voice or noise below a certain level, and converts only the signal over the appropriate level to a binary level, that is, OV and + 8V. DC support capacitor for cycle, so

The waveform of the point is shown in Figure 2b.

This waveform is again inverted by the inverter 4 to make the signal pause period HIGH, and is applied to the first integrating circuit 22 configured as the diode 5, the resistors 6, 7 and the capacitor 8. . In the integrating circuit, the diode (5) is for different charging and discharging time constants. The charging is only through the resistor (7), the time constant is 12ms, and the discharge is made through both the resistors (6) and (7). Is 2ms.

점의 파형은 제2도의 d 그림과 같이 되며 인버터(9), (10)에 의해 정확한 구형파로 만들어진다. 다이오드(11), 저항(12) 및 콘덴서(13)는 다시 제2 적분회로(23)를 구성하며, 다이오드(11)에 의한 순간충전과 저항(12)를 통한 방전은 100ms동안에 이루어진다.Therefore, only components below 100 Hz are detected

The waveform of the point is as shown in the d diagram of FIG. The diode 11, the resistor 12 and the capacitor 13 again constitute the second integrating circuit 23, and the instant charging by the diode 11 and the discharge through the resistor 12 are performed for 100 ms.

점의 파형은 제2도g 그림과 같게되며

점에 도달한 신호(여기서는 음성휴지신호를 나타낸다)중 지속시간 70ms이하의 것은 인버터(14)를 지나면서 제거된다. 즉 동기형 4비트 카운터(17)의 SR입력단자에는 제1, 제2 적분회로를 지나는 동안 신호지속시간이 80ms이상인 것만 인가되는 반면, C입력단자에는 10ms이상인 신호가 반전된 형태로 모두 인가되고 있다.therefore

The waveform of the point is shown in Figure 2 g.

Among the signals that reach the point (here, the voice stop signal is shown), a duration of 70 ms or less is removed while passing through the inverter 14. That is, only the signal duration time of 80 ms or more is applied to the SR input terminal of the synchronous 4-bit counter 17 while passing the first and second integrating circuits, while the signal of 10 ms or more is applied to the C input terminal in an inverted form. have.

As described above, the synchronous 4-bit counter 17 performs a counting operation when an L → H transition occurs in the C terminal while the SR terminal is HIGH, and outputs it to the output terminal TC when 16 pulses are continuously counted. On the other hand, if L → H transition occurs in C while SR is LOW, the counting content in progress is reset. However, comparing the figure f and h in Fig. 2, when pulse ①② of f makes L → H transition, the pulse of h is still high, so it is counted, but the transition of L → H of ③④⑤ of f is followed by h As it happens in LOW state, the counting content is erased so far. For the same reason, counting is done on pulse ⑥⑦ of f, but subsequent pulse ⑧⑨⑩⑪⑫ is reset.

Due to the irregularity of the amplitude and interruption time of the voice, the likelihood that the counter 17 can complete 16 counters while the voice continues is probabilistically close to O, thus enabling the detection of the voice signal.

점에 HIGH신호가 있어야 출력단(Q7)이 HIGH로 된다.On the other hand, the oscillator 18 generates a square wave with a period of 40 ms, and the counter 19 is configured to have a function of dividing it by 1/256 for 256 pulse periods (about 10 seconds).

HIGH signal is present at the point to output high (Q7).

However, while the audio signal is being applied, since the HIGH signal is continuously applied to the reset terminal R of the counter 19 as shown in FIG. 2, the counter 19 can output an output signal. Putting both cases together, the counters 17 and 19 can both output while the voice continues. In sum, the counters 17 and 19 cannot both output while the voice continues, so that the OR gate 20 continues to be recorded.

점에서는 톤 길이가 거의 동일한 길이를 갖는 구형파가 이루어진다. 이것은 한편으로 제3도j 그림과 같은 파형이 되어 카운터(19)를 계속 리셋트하여 동작치 못하게 하며, 또한

점에서는 반전된 신호로서 나타난다. 다시 제2적분 회로를 거치는 동안 신호길이가 축소되나

점에는 단축된 신호가 틀림없이 나타난다. 따라서 제3도f 그림의

펄스는 모두 카운팅이 되며, 만약 16개의 톤 펄스가 인가되면 카운터(17)는 출력을 발생하여 오어게이트(20)을 거쳐 통화가 끝났음을 자동전화 응대장치의 제어부에 전달함으로써 장치를 다시 대기상태로 전화시킨다.The following describes the case in which the caller, dial tone, etc. from the switchboard is applied to the circuit after the caller hangs up. The mechanical sound from the switchboard has a constant amplitude because the tone duration is at least 150 ms and the sound from the oscillator. Therefore, no signal is interrupted by the Schmitt trigger circuit 2

At this point, a square wave with a length of approximately the same tone length is formed. On the one hand, this becomes a waveform as shown in Fig. 3J, which continuously resets the counter 19 to render it inoperable.

At the point it appears as an inverted signal. While the signal length is reduced while going through the second integrating circuit again,

A shortened signal must be present at the point. Thus, in Figure 3

The pulses are all counted, and if 16 tone pulses are applied, the counter 17 generates an output and sends the device to the control unit of the automatic telephone answering device that the call is over via the orgate 20 to bring the device back to standby. Call

점은 LOW,

점은 HIGH상태가 되며 따라서

점은 LOW상태가 되어 카운터(19)의 출력단자(Q7)에서 10초후 출력신호가 나오고 이것은 OR게이트(20)를 경유하여 통화가 종료되었음을 알라게 된다. 한편

는 LOW,

는 HIGH상태만을 유지하므로 카운터(17)는 작동치 않는다.Explain that when the caller hangs up the phone and makes a continuous tone at the switchboard,

The point is LOW,

Point becomes HIGH, so

The point becomes LOW state and an output signal comes out after 10 seconds from the output terminal Q7 of the counter 19, which indicates that the call is terminated via the OR gate 20. Meanwhile

Is LOW,

Keeps the HIGH state, so the counter 17 does not operate.

점은 HIGH

점은 LOW가 되므로

점과 LOW상태가 되어 역시10초 카운터(19)가 작동통화가 끝났음을 알린다. 이 동안도 역시 카운터(17)은 작동치 않는다.Also, if the caller hangs up and explains that there is no tone on the switchboard and remain silent.

Point is HIGH

As the point becomes LOW

The dot and the LOW state is also 10 seconds counter (19) to inform the end of the active call. The counter 17 also does not work during this time.

As described above, the present invention uses the Schmitt trigger circuit and the integrating circuit as appropriate to discriminate between the voice and the mechanical sound in terms of regularity of the intermittent packet, and to prevent the malfunction due to the regular sound that may be generated during the voice call. By using the counter to reclassify in probabilistic terms, it provides a new circuit for reliable voice discrimination regardless of the type of link exchange.

Claims (1)

A voice discrimination circuit used in an automatic telephone answering device, which connects a first integrating circuit 22 that filters only components below a specific frequency among input signals and a shaping circuit of inverters 9 and 10 shaping it into a square wave, The signal detected by the second integrating circuit 23 is sequentially counted by connecting the second integrating circuit 23 that detects only the signal duration time lasting more than a certain time and the inverter 14 shaping the square wave. 2. A speech discrimination circuit configured to distinguish between the sound and the intermittent sound of the mechanical sound by connecting a synchronous counter 17 to reset the count content of the short duration signal removed from the integrating circuit 23.

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