JPS63299528A - Multi-frequency signal receiver - Google Patents

Abstract

PURPOSE:To ensure the accurate reception of the multi-frequency signal transmitted from the terminal side even in a transmission state of an aural guidance, by using a circuit which estimates the reflected wave signal received from a 4-wire terminal of a 2-wire/4-wire converter and a circuit which subtracts said reflected wave signal from the output signal of the 4-wire terminal. CONSTITUTION:In case s multi-frequency signal is supplied from an input/output terminal 1 in the midst of the output of an aural guidance of an aural guidance output circuit 3, a mixed wave of the reflected wave of the aural guidance and the multi-frequency signal is outputted to the 4-wire output terminal side of a 2-wire/4-wire converter 2. In a reflected wave estimating circuit 11, a reflected wave is estimated and supplied to a subtraction circuit 12. Then only the reflected wave component of the aural guidance signal is subtracted from a mixed wave of the reflected wave of the aural guidance signal and the multi- frequency signal containing the low and high group frequencies. Then only the multi-frequency signal component is supplied to a signal detecting circuit 4. Thus it is possible to prevent the misreception of the multi-frequency signal that is caused by the reflected wave of the aural guidance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multi-frequency signal receiver in a voice response device or a voice distribution device, etc., and is used when transmitting signals and data from a center device or terminal to terminal. The present invention relates to a multi-frequency signal receiver.

[Prior Art] Conventionally, multi-frequency signal receivers, especially multi-frequency signal receivers used to transmit signals and data from one terminal to another using multi-frequency signals, suffer In Japan, the signal reception level range was very wide, from -5 to -48 dBm.

Especially when used as one terminal or center device,
After the center equipment is connected to a terminal such as a subscriber telephone, voice guidance for various services is sent from the center equipment to the terminal side, and the terminal side sends out multiple voice guidance for the purpose of identifying the type of service request. Frequency signals are used. In this case, when a guidance voice signal is output from the center equipment, reflected waves are generated due to impedance mismatch at the connection point between the center equipment and the subscriber line, or the connection point between the subscriber line and the exchange. do.

Therefore, if a multi-frequency signal is sent from the terminal side while a guidance audio signal is being output from the center equipment, the multi-frequency signal receiver on the center side receives the reflected wave of the audio signal and the multi-frequency signal. There are many problems where signals are mixed and input, and multi-frequency signals are not received or multi-frequency signals are received incorrectly.

Therefore, in conventional multi-frequency signal receivers of this type, -
For example, as shown in FIG. 2, when outputting a guidance voice signal, a method was adopted in which the human power of the multi-frequency signal was cut off.

That is, in FIG. 2, l is a two-wire input/output terminal,
2 is a 2-wire 4-wire conversion circuit, 3 is a voice guidance output circuit,
4 is a signal detection circuit, 5 is an input control circuit for the signal detection circuit 4, and 6 is a control circuit. When the voice guidance output circuit 3 outputs the voice guidance to the input/output terminal l via the 2-wire 4FI conversion circuit 2 according to the control signal from the control circuit 6, the control circuit 6 simultaneously receives the multi-frequency signal. A control signal is input to the input control circuit 5 of the device 7 to prevent the two-wire four-wire circuit 2 and the multi-frequency signal receiver 7 from being connected.

This prevents the reflected waves of the voice guidance from being input to the multi-frequency signal receiver 7, thereby preventing erroneous reception of the multi-frequency signal due to the reflected waves.

[Problems to be solved] In the conventional multi-frequency signal receiver described above, the input to the multi-frequency signal receiver is cut off while audio guidance is being sent out. It was not possible to receive multi-frequency signals from the terminal side, and it was only possible to receive multi-frequency signals from the terminal side after voice guidance transmission had finished. Therefore, for the subscriber on the terminal side, the multi-frequency signal is only sent out when voice guidance is not being sent out, resulting in a problem of very poor service quality.

The present invention has been made in view of the problems described in J-.
To provide a multi-frequency signal receiver that can accurately receive multi-frequency signals sent from a terminal side even while audio guidance is being sent.

[Means for Solving Problems] In order to achieve the above object, the multi-frequency signal receiver of the present invention provides if? 21a4, which occurs when the audio guidance signal is output from the guidance output circuit to the 2-wire 4-wire conversion circuit.
A reflected wave prediction circuit predicts the reflected wave signal from the 4-wire terminal of the line conversion circuit, and the reflected wave signal rumored to be 1,000A1 is converted to the 2-wire 4
The configuration includes a subtraction circuit that subtracts from the 4-wire terminal output signal of the line conversion circuit. Preferably, the reflected wave prediction circuit subtracts the output signal from the voice guidance output circuit and the 4-wire terminal output signal of the 2-wire 4-wire conversion circuit. The structure is such that a transfer function is determined based on a terminal output signal and a reflected wave signal is predicted.

[Embodiment] Hereinafter, one embodiment of the present invention will be described based on FIG. 1.

FIG. 1 is a block diagram of a multi-frequency signal receiver according to this embodiment.

In FIG. 1, l is an input/output terminal of the voice service device and is connected to a 2-wire/4-wire conversion circuit 2. In FIG. A control circuit 6 is connected to the voice guidance output circuit 3 and the signal detection circuit 4.

The output of the audio guidance output circuit 3 is input to the 4-wire input terminal of the 2-wire/4-wire conversion circuit 2, and is also input to the reflected wave prediction circuit 11 of the multi-frequency signal receiver 10. The 4-wire terminal of the 2-wire 4-wire conversion circuit 2 is connected to the reflected wave prediction circuit 11 and the subtraction circuit 12, and the output of the subtraction circuit 12 is input to the signal detection circuit 4 to detect multifrequency characteristics. .

When voice guidance is output from the voice guidance detection circuit 3, it is sent to the input/output terminal l via the 2-wire 4-wire conversion circuit 2.
However, due to impedance mismatch during 2-wire 4-wire conversion, a reflected wave is output to the 4-wire output terminal of the 2-wire 4-wire conversion circuit 2. At this time, the 1-reflected wave prediction circuit 11 calculates a transfer function from the 4-wire terminal output of the audio guidance output circuit 3 and the 2-wire 4-wire conversion circuit 2, and predicts the reflected wave.

The reflected wave predicted in this way is input to the subtraction circuit 12 and subtracted from the 4&Ia terminal output of the 2-wire 4-wire conversion circuit 2, and only the reflected wave is input to the signal detection circuit 4.

If a multi-frequency signal is input from the input/output terminal l while voice guidance is being output from the voice guidance output circuit 3, the reflected wave of the voice guidance will be sent to the 4-wire output terminal side of the 2 & 14-wire conversion circuit 2. A mixed wave of the multi-frequency signals is output and input to the subtraction circuit 12. Reflected wave prediction circuit 11
Then, as described above, the reflected wave for the sound guidance signal is pre-prepared and input to the subtraction circuit 12. Therefore, the subtraction circuit 12 subtracts only the reflected wave component of the voice guidance signal from the mixed wave of the reflected wave of the voice guidance signal and the multi-frequency signal of the low group frequency and the high group frequency, and subtracts only the reflected wave component of the voice guidance signal. 4, only multifrequency signal components are input. Thereby, the multi-frequency signal detection result detected by the signal detection circuit 4 is accurately notified to the control circuit 6.

In this way, the multi-frequency signal receiver of this embodiment, when transmitting K-voice guidance, detects the reflections that occur from the output voice guidance at the connection point between the center equipment and the subscriber line, and at the connection point between the subscriber line and the exchange. By predicting the wave signal and removing it from the input of the multifrequency signal receiver, it is possible to prevent erroneous reception of the multifrequency signal due to reflected waves of the voice guidance.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent erroneous reception of multi-frequency signals due to reflected waves of voice guidance. This has the effect of correctly receiving a multi-frequency signal even when a signal is input.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a multi-frequency signal receiver according to an embodiment of the present invention;
FIG. 2 shows a configuration diagram of a conventional multi-frequency signal receiver. 1: Input/output terminal 2: 2-wire 4-wire conversion circuit 3: Voice guidance output circuit 4; Signal detection circuit 6: Control circuit 1O: Multi-frequency signal receiver

Claims (2)

[Claims] (1) 2-wire 4 generated when the audio guidance signal is output from the audio guidance output circuit to the 2-wire 4-wire conversion circuit
A reflected wave prediction circuit that predicts a reflected wave signal from the 4-wire terminal of the line conversion circuit, and a subtraction circuit that subtracts the predicted reflected wave signal from the 4-wire terminal output signal of the 2-wire and 4-wire conversion circuit. A multi-frequency signal receiver featuring: (2) The reflected wave prediction circuit calculates a transfer function based on the output signal from the voice guidance output circuit and the 4-wire terminal output signal of the 2-wire 4-wire conversion circuit, and predicts the reflected wave signal. A multi-frequency signal receiver according to claim 1.