JPH0289427A - Multi-frequency signal receiver - Google Patents

Abstract

PURPOSE:To attain the reception of a multi-frequency signal even in the transmission of a voice guidance by predicting a reflection wave signal from the voice guidance outputted in the transmission of the voice guidance and eliminating the reflection wave signal from the input of a multi-frequency receiver. CONSTITUTION:If a multi-frequency signal is inputted from an input/output terminal 4 during an output of a voice guidance (a) from a voice guidance output circuit, a signal (b) being a mixed wave between a reflected wave of the guidance (a) and a multi-frequency signal is outputted from a 4-wire output terminal 9 of a 2/4-wire conversion circuit 5. On the other hand, a reflection wave prediction circuit 1 predicts a reflected wave component to the guidance (a) and the predicted value is inputted to a subtraction circuit 2. The circuit 2 subtracts only a reflected wave component (c) of the guidance (a) from the signal (b) and outputs the result to a signal detection circuit 3. The circuit 3 detects a multi-frequency component from the inputted multi-frequency signal component. The result of detected multi-frequency signal is informed to a control circuit 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multi-frequency signal receiver, and particularly to a multi-frequency signal receiver used for transmitting signals and data in a center device or terminal-to-terminal communication. Relating to a signal receiver.

[Conventional technology]

When a center device or one terminal communicates with another terminal, after a communication path is established between the center device or one terminal and the other terminal, one terminal or center device sends information for various services. A multifrequency signal may be used for the purpose of transmitting voice guidance and identifying the type of service request from another terminal to one terminal or a center device.

A multi-frequency signal receiver receives and detects such multi-frequency signals.

By the way, when voice guidance is sent out, an echo signal of this voice guidance is generated due to an impedance mismatch at the connection point between the subscriber line and the exchange, and it may loop around to the terminal or center equipment on the voice guidance sending side. . On the other hand, the signal level varies significantly depending on the amount of attenuation of the transmission path from terminal to terminal, and in Japan, the signal reception level range is extremely wide from -5 to -48 dBmO. Therefore, the multi-frequency signal receiver also supports this wide range of signal reception levels, and the echo signal is also received by the multi-frequency signal receiver. Therefore, if a multi-frequency signal is sent from the terminal side while a guidance audio signal is being output from the center device, the echo component of the audio signal and the multi-frequency signal are mixed and input to the multi-frequency signal receiver on the center side. Therefore, the multi-frequency signal receiver on the center side often fails to recognize the multi-frequency signal or receives the multi-frequency signal incorrectly, which poses a problem.

To solve this problem, multifrequency signal receivers include a method of cutting off the input of the multifrequency signal when a guidance audio signal is output, and a method of disabling the multifrequency reception result by software. FIG. 2 is an example of such a multi-frequency signal receiver, and is a block diagram of a multi-frequency signal receiver that cuts off the multi-frequency input (no. 8) when a guidance audio signal is output. Fig. 2 shows a state in which this multi-frequency signal receiver is applied to a voice response device comprising a 2-wire/4-wire conversion circuit 14, a voice guidance output circuit 15, and a control circuit 16. In, the control circuit 1
6, the audio guidance output circuit 15 outputs audio guidance. This audio guidance is output to the input/output terminal 13 via the 2-wire/4-wire conversion circuit 14. On the other hand, the echo signal of the voice guidance is input to the input control circuit 11 from the output of the 2-wire/4-wire conversion circuit 14.

At this time, since the control circuit 16 is outputting voice guidance, it controls the input control circuit 11 to
The signal to 2 is cut off. This prevents the echo signal of the voice guidance from being input to the signal detection circuit 12 and prevents malfunctions due to voice input.

[Problem that the invention seeks to solve]

The above-mentioned conventional multi-frequency signal receiver has the disadvantage that the input to the multi-frequency signal receiver is cut off while the voice guidance is being sent out, so the multi-frequency signal cannot be received while the voice guidance is being sent out. be. Then, the multi-frequency signal can be received for the first time after the voice guidance ends. This situation provides poor service to the users on the multi-frequency signal sending side, and mutual communication takes much time and is not efficient.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and provide a multi-frequency signal receiver that can receive multi-frequency signals even when voice guidance is being transmitted.

[Means for solving problems]

The present invention provides a multi-frequency signal receiver that removes a reflected wave component from a mixed signal consisting of a reflected wave of voice guidance and a multi-frequency signal outputted from a voice guidance output circuit, which includes: voice guidance from the voice guidance output circuit; and,
a reflected wave prediction circuit that predicts the reflected wave component of the audio guidance from the input mixed signal; a subtraction circuit that removes the reflected wave component predicted by the reflected wave prediction circuit from the input mixed signal; Is it a subtraction circuit?
The present invention is characterized in that it has a signal detection circuit that detects a multifrequency signal from a mixed signal from which reflected wave components have been removed, which is output from the mixed signal.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of the present invention.

In addition, in FIG. 1, the present invention is a two-wire four-wire conversion circuit 5. Voice guidance output circuit 6. A state in which it is applied to a voice response device including a control circuit 7 is shown. This multi-frequency signal receiver receives the reflected wave component of the audio guidance a from the audio guidance a output from the audio guidance output circuit 6 and the signal output from the 4-wire output terminal 9 of the 2-wire 4-wire conversion circuit 5. A reflected wave prediction circuit 1 for predicting, a subtraction circuit 2 for removing the reflected wave component C predicted by the reflected wave prediction circuit 1 from the signal, and a signal detection circuit for detecting a multifrequency signal from the signal d output from the subtraction circuit 2. It consists of 3.

In the voice response device having such a multi-frequency signal receiver, the voice guidance output circuit 6 outputs voice guidance a for various services in response to instructions from the control circuit 7. This audio guidance a is inputted to the terminal 8 of the 2-wire 4vA conversion circuit 5, and further outputted from the input/output terminal 4.

On the other hand, a reflected wave that is an echo signal of this voice guidance a and a multi-frequency signal for the purpose of identifying the type of service request from the other party's device in response to this voice guidance are input to the input/output terminal 4, and are input to the input/output terminal 4. It is output from the 4-wire output terminal 9 of the conversion circuit 5.

Next, the operation of this embodiment will be explained.

When the audio guidance a is output from the audio guidance output circuit 6, the audio guidance a is output to the input/output terminal 4 via the 2-wire/4-wire conversion circuit 5. At this time, a reflected wave of the audio guidance a is output to the four-wire output terminal 9 of the two-wire four-wire conversion circuit 5 due to impedance mismatch during the two-wire four-wire conversion. On the other hand, the reflected wave prediction circuit 1 calculates a transfer function from the output of the audio guidance output circuit 6 and the 4-wire output terminal 9 of the 2-wire 4-wire conversion circuit 5, and predicts the reflected wave component. The predicted reflected wave component C is input to the subtraction circuit 2. Since the subtraction circuit 2 subtracts the predicted reflected wave component C from the signal b output from the 2-line and 4-line conversion circuit 5, that is, the reflected wave, no signal is input to the signal detection circuit 3.

Next, the audio guidance a is output from the audio guidance output circuit 6.
If a multifrequency signal is input from the input/output terminal 4 during output, a signal that is a mixed wave of the reflected wave of the voice guidance a and the multifrequency signal is output from the 4-wire output terminal 9 side of the 2vA 4-wire conversion circuit 5. Output.

On the other hand, the reflected wave prediction circuit 1 predicts the reflected wave component for the audio guidance a, and inputs it to the subtraction circuit 2. Since the signal is a mixed wave of the reflected wave of the voice guidance a and a multi-frequency signal, the subtraction circuit 2 calculates the reflected wave component C of the voice guidance a.
is subtracted and output to the signal detection circuit 3. The signal detection circuit 3 detects a multifrequency signal from input multifrequency signal components.

The detected multi-frequency signal detection result is notified to the control circuit 7.

In this way, in this embodiment, when transmitting voice guidance, the reflected wave signals generated at the connection point between the center equipment and the subscriber line, or the connection point between the subscriber line and the exchange are predicted from the output voice guidance, and the reflected wave signal is The signal can be removed from the input of the receiver.

〔Effect of the invention〕

As explained above, the present invention has the effect of preventing erroneous reception of multi-frequency signals due to the reflected waves of voice guidance, and even if a multi-frequency signal sent from the terminal side is input while voice guidance is being transmitted. This has the effect of correctly receiving multi-frequency signals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional multi-frequency signal receiver. 1...Reflected wave prediction circuit 2...Subtraction circuit 3...Signal detection circuit 4...Input/output terminal 5...2-wire 4-wire conversion circuit 6...Voice guidance output circuit 7... control circuit

Claims (1)

[Claims] (1) From a mixed signal consisting of a reflected wave of voice guidance output from a voice guidance output circuit and a multifrequency signal,
In a multi-frequency signal receiver that removes reflected wave components, voice guidance from the voice guidance output circuit;
a reflected wave prediction circuit that predicts a reflected wave component of the audio guidance from an input mixed signal; a subtraction circuit that removes the reflected wave component predicted by the reflected wave prediction circuit from the input mixed signal; A multi-frequency signal receiver comprising: a signal detection circuit that detects a multi-frequency signal from a mixed signal from which a reflected wave component has been removed, which is output from a subtraction circuit.