JPH02164175A - Voice reply device - Google Patents

Abstract

PURPOSE:To prevent bypass of a voice message signal to a PB signal receiver by applying adaptive control to a weight coefficient of a tap of an FIR filter when a signal power of 4-wire side input is larger than a signal power of 4-wire side output by a prescribed value. CONSTITUTION:A power comparator 30 compares the 4 wire input side signal power of a 2/4-wire conversion means 10 with a signal power of a 4-wire output, and when the former signal power is larger than the latter signal power by a prescribed value or over, a control start signal is outputted to an FIR filter 41. The FIR film applies adaptive control of a weight coefficient of a tap to revise the weight coefficient so that the output of an adder is close to zero. In this case, the output signal of the FIR filter 41 predicts a voice message signal bypassed from the 4 wire side input to the 4 wire side output of the 2/4-wire conversion means 10. As a result, the voice message signal bypassed via the 2/4-wire conversion means 10 is cancelled by the output of the adder 42 and not inputted to a PB signal receiver 64.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is connected to a two-wire subscriber line, and transmits a PB double signal pressed and sent by the subscriber to the connected subscriber line, and therefore transmits audio to that subscriber. The present invention relates to a voice response device that selectively sends messages.

[Conventional technology]

An example of a conventional voice response device is shown in FIG. lO is 2 lines/4! The la conversion means consists of a 2'la/4 line conversion circuit and a subscriber line termination circuit, 20 is an encoder, 21 is a decoder, 50.51 is a selector, 61 is a melody generator, 6
2 is a PB signal transmitter, 63 is an audio storage circuit, and 64 is a PB signal transmitter.
It is a signal receiver, and selectors 50 and 51 are connected as shown by dotted lines in order to monitor the PB double signal sent from the destination subscriber while a voice message is being sent. and,
The voice message signal output from the voice storage circuit 63 is inputted to the encoder 20 through the selector 50, encoded by the encoder 20, and then sent to the subscriber line through the 2-wire/4-wire conversion means 10. Further, a PB double signal sent from the connected subscriber through the subscriber line is given to the decoder 21 from the 2-wire/4-wire conversion means 10, and after being decoded, is input to the PB signal receiver through the selector 51. be done.

[Problem to be solved by the invention]

Such conventional voice response devices have the following problems. That is, in the conventional voice response device, since the device is connected to the subscriber line, the PB signal receiver 64 is a PB signal receiver (End-to-end) with a wide dynamic range.
- for End) is used.

However, as the dynamic range of the PB signal receiver increases, the probability of detecting the sound as a PB multiplied signal (
This has the disadvantage that the probability of not receiving the PB (8) that should be received increases due to the increase in the voice malfunction rate (voice malfunction rate) and the mixing of noise from other sources. The 4-wire conversion means 10 cannot sufficiently attenuate the amount of input signal on the 4-wire side that goes around to the output on the 4-wire side, and can only secure an attenuation amount of about 20 to 30 dB.

Therefore, the voice message signal is
The PB signal receiver 64 is attenuated by 20 to 30 dBM and has a wide dynamic range. However, the inconvenience arises in that the voice message signal that goes around via the 2-wire/4-wire conversion means 10 is detected as a PB multiplied signal. Also, when a subscriber sends a PB double signal, the looping voice message signal and the PB double signal are added, and the PB signal reception is
This causes an inconvenience in that the PB-multiple signal that the device 64 should originally receive and detect is not detected.

To further explain with reference to FIG. 4, which functionally represents the voice response device of FIG. 3, the voice message signal sent out from the voice storage circuit 63 at = 20 to 30) and goes around to the PB signal receiver, and since the input dynamic range of the PB signal receiver 64 is -48 to -5 dBm, the PB signal receiver 64 receives a voice message signal with 28 dBm≦X. This means that the signal is multiplied by PB and detected.

Further, the frequency of the voice message signal, that is, the voice signal, and the PB double signal frequency have a relationship as shown in FIG. 5, and the voice signal includes the PB double signal frequency component. Therefore, if a voice message signal reaches the PB signal receiver at the above-mentioned level, it will be detected as a PB multiplied signal. In addition, when the voice message signal goes around and is added to the PB double signal, the high group wave component and low group wave component, which are the fundamental wave components of the PB double signal, are disturbed, and the limiter circuit inside the PB signal receiver disturbs the fundamental wave components of the PB double signal. It becomes difficult to separate the wave components, and it becomes impossible to receive the PB multiplied signal that should originally be received.

SUMMARY OF THE INVENTION An object of the present invention is to provide a voice response device that solves these problems and prevents a voice message signal from going around to a PB signal receiver.

[Means to solve the problem]

The present invention provides an audio storage means for storing a voice message signal, a PB signal receiving means for receiving a PB multiplied signal, an output of the audio storage means is connected to a 4-line side input, and an output of the 4-line side is connected to the PB signal.
The voice message signals supplied to the inputs of the signal receiving means and output by the voice storage means are sent to the two-wire subscriber line, and the PB multiplied signal from the two-wire subscriber line is
2-wire/4-wire conversion means for supplying a signal to a signal receiving means; and a first signal power of the 4-wire side input of the 2-wire/4-wire conversion means; Compare the output with the second signal power,
power comparison means for outputting a control start signal when the first signal power is greater than the second signal power by a predetermined value or more; and filtering the signal of the 4-wire side input of the 2-wire/4-wire conversion means. and the FIR filter that outputs the 2-wire/4
provided between the line converting means and the PB signal receiving means,
and subtraction means for subtracting the output signal of the FIR filter from the signal of the 4-wire side output of the 2-wire/4'ft1A conversion means and outputting the result to the PB signal receiving means, the FIR filter comprising: The present invention is characterized in that when the power comparison means outputs the control start signal, the weighting coefficients of the taps are adaptively controlled so that the output signal of the subtraction means approaches zero.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a voice response device according to the present invention. In the figure, the same components as in FIG. 3 are given the same reference numerals. In FIG. 1, 10 is a 2-wire/4-wire conversion means; 2. */ Consists of a 4-wire conversion circuit and a subscriber line termination circuit, 20 is an encoder, 21 is a decoder, 30 is a power comparator, and 40 is an FI R (Finite Impulse) circuit.
an echo canceller consisting of a filter 41 and an adder 42; 50.51 is a selector;
1 is a melody generator, 62 is a PB signal transmitter, 63 is an audio storage circuit, and 64 is a PB signal receiver. And a melody generator 61. PB signal transmitter 62. The outputs of the audio WM circuit 63 are also connected to the inputs of a selector 50, and the output of the selector 50 is connected to the input of the encoder 20, one input of the comparator 30, and the signal input of the FIR filter 41. The subscriber line termination circuit of the 2-wire/4-wire conversion means 10 is connected to the subscriber line, and the 4-line side input is connected to the encoder 2.
0 output, and the 4-wire side output is connected to the input of the decoder 21, respectively. The output of the decoder 21 is connected to the other input of the comparator 30 and the non-inverting input of the adder 42, and the output of the adder 42 is connected to the FIR filter 41.
is connected to the first control input of the selector 51 and the input of the selector 51. Further, one output of the selector 51 is connected to the input of the audio storage circuit 63, and the other output is connected to the PB signal receiver 640 input. The second control input of the FIR filter 41 is connected to the output of the comparator 30, and the signal output of the FIR filter is connected to the inverting input of the adder 42.

FIG. 2 is a functional representation of the voice response device configured as described above, and particularly shows the case where the selectors 50 and 51 are connected as shown by dotted lines.

Next, the operation will be explained using this diagram. Audio storage circuit 63
When a voice message signal is output from I'l
After being input to the R filter 41 and subjected to filter processing, it is input to the inverting input of the adder 42. Further, the voice message signal from the voice storage circuit 63 is transmitted to the 2-wire/4-wire conversion means 1.
From the 4-wire side input of 0 to the 4-wire side output, the adder 42
is input to the non-inverting input of Here, the audio storage circuit 63
The voice message signal output from is xdBm,
If the attenuation in the 2-wire/4-wire conversion means is αdBm, then X-
The αdBm voice message signal is input to the adder 42. At this time, the power comparator 30 compares the signal power of the 4-wire side input of the 2-wire/4-wire conversion means 10 with the signal power of the 4-wire side output, and the former signal power is higher than the latter signal power by a predetermined value. When the value is greater than the value, a control start signal is output to the FIR filter 41. As a result, the FIR filter performs adaptive control of the weighting coefficients of the taps, and updates the weighting coefficients so that the output of the adder approaches zero. At this time, the output signal of the FIR filter 41 is a predicted voice message signal that has passed from the 4-wire input to the 4-wire output of the 2-wire/4-wire conversion means 10. As a result, the voice message signal that has passed through the 2-wire/4-wire conversion means 10 is canceled at the output of the adder 42, and the PI3 signal receiver 6
4 is not entered. Therefore, P of the voice message signal
The conventional problem associated with the loopback to the B signal receiver side is solved.゛If the signal at the non-inverting input of the adder 42 is mixed with the connected subscriber's voice or PB multiplied signal, the FIR
The filter 41 cannot predict the feedback component of the voice message signal and the adaptive control will not converge, so in such a case it is necessary to stop the adaptive control.

The power comparator 30 is provided for this purpose; if the signal mentioned above is mixed, the signal power of the 4-wire side output increases, so the power comparator 30 does not output a control start signal, and the FIR filter does not perform adaptive control.

〔Effect of the invention〕

As explained above, the present invention includes an audio storage means for storing a voice message signal, a PB signal receiving means for receiving a PB multiplied signal, an output of the audio storage means is input to the 4-wire side, and an output from the 4-wire side is the PB signal. The voice message signals supplied to the inputs of the receiving means and output by the voice storage means are sent to the two-wire subscriber line, and the PB multiplied signal from the two-wire subscriber line is received (to be supplied to the ε means). 2-wire/4-wire conversion means, the first signal power of the 4-wire side input and the second signal power of the 4-wire side output of the 2-wire/4-wire conversion means. power comparison means for comparing and outputting a control start signal when the first signal power is greater than the second signal power by a predetermined value; FIR filter that outputs
provided between the 4-wire conversion means and the PB signal reception means;
subtraction means for subtracting the output signal of the FIR filter from the signal of the 4-wire side output of the wire/4-wire conversion means and outputting the result to the PB signal receiving means; When output, the weight coefficients of the taps are adaptively controlled so that the output signal of the subtraction means approaches zero.

Therefore, in the voice response device of the present invention, the voice message signal that has passed through the 2-wire/4-wire converting means is canceled at the output of the subtracting means and is not input to the PB signal receiving means. Therefore, the conventional problem associated with the looping of the voice message signal to the PB signal receiving means side is solved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the voice response device according to the present invention; FIG. 2 is a functional block diagram showing functionally a portion of the voice response device shown in FIG. 1 particularly related to the invention; The figure is a block diagram showing an example of a conventional voice response device, FIG. 4 is a functional block diagram showing the parts of the voice response device of FIG. 3 that are particularly related to the invention, and FIG. It is a graph showing the relationship with the PB double signal frequency. 10・ ・ ・ 20・ ・ ・ 21・ ・ ・ 30・ ・ 40・ ・ ・ 41・ ・ 42・ ・ ・ 50.51・ 61・ ・ ・ 62・ ・ ・ 63・ ・ ・ 64・ ・ ・ 2 lines /4-wire conversion means encoder decoder power comparator echo canceller FIR filter adder selector melody generator PB signal transmitter audio storage circuit PB signal receiver

Claims (1)

[Claims] (1) voice storage means for storing voice message signals;
PB signal receiving means for receiving a PB signal; the output of the audio storage means is supplied to a 4-wire side input; the 4-wire side output is supplied to an input of the PB signal receiving means, and the audio storage means outputs an audio message. A voice response device comprising 2-wire/4-wire conversion means for sending a signal to a 2-wire subscriber line and supplying a PB signal from the 2-wire subscriber line to the PB signal receiving means, Comparing the first signal power of the 4-wire side input of the 2-wire/4-wire conversion means and the second signal power of the 4-wire side output,
power comparison means for outputting a control start signal when the first signal power is greater than the second signal power by a predetermined value or more; and filtering the signal of the 4-wire side input of the 2-wire/4-wire conversion means. and the FIR filter that outputs the 2-wire/4
provided between the line converting means and the PB signal receiving means,
The output signal of the FIR filter is subtracted from the signal of the 4-wire side output of the 2-wire/4-wire conversion means, and the result is subtracted from the PB.
subtraction means for outputting to the signal reception means, the FIR filter adaptively controls the weighting coefficient of the tap so that the output signal of the subtraction means approaches zero when the power comparison means outputs the control start signal. A voice response device characterized by: