JPS61147651A - Automatic answering telephone set - Google Patents

Abstract

PURPOSE:To raise the discrimination rate to perform accurate remote control by providing an automatic gain adjusting means, which suppresses the reception signal level of a PB signal, in the preceding state of a PB signal receiving and demodulating means and discriminating always accurately the PB signal independently of the reception signal level. CONSTITUTION:An automatic gain adjusting (AGC) circuit 8 is provided in the preceding state of a dial signal demodulating means 4. When an owner operates prescribed dial buttons during the transmission of a response message or within a prescribed time after the end of the transmission to send the PB signal for the purpose of changing the communication destination or the like from the place where he is staying. This PB signals is led to the AGC circuit 8 through a changeover switch 7, and the reception signal level is adjusted by the AGC circuit 8. Since the AGC circuit 8 is provided with the first and the second time constant circuits to set properly an attack time and a recovery time, AGC is performed surely without influences of the voice signal of the response message even if the PB signal comes during the transmission of the response message, and thus, accurate discrimination is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an answering machine whose response operation can be remotely controlled from an outside line. (Technical Background of the Invention) In recent years, answering machines have been widely used in homes, offices, etc., and by sending a PB signal from an outside line into the answering machine, responses such as changing the content of a response message can be sent. There is a device whose operation can be controlled remotely. Fig. 2 is a circuit block diagram showing an example of its configuration. In the figure, this device has a receiving circuit 1, a dialing circuit 2,
It has a telephone communication system consisting of a hook switch H8 and an automatic call response circuit 3, and also has a dial signal detection system consisting of a dial signal demodulating means 4 and a dial signal discriminating means 5. The telephone communication system and an answering system consisting of an automatic call answering circuit 3 and a dial signal detection system are selectively connected to the telephone line 6 by a changeover switch 7.

However, when the selector switch 7 is set to the answering system side, the lever device enters the answering mode. When an incoming call signal arrives from the caller in this state, this incoming signal is detected by the incoming call detecting section of the automatic incoming call answering circuit 3, and as a result, the voice generating circuit provided in the automatic incoming call answering circuit 3 makes a preset setting. The predetermined response message is sent to the telephone line 6.

Further, when a predetermined PB signal is sent by the caller by operating the dial button after the sending of this response message is completed, this PB signal is received and demodulated by the dial signal IIi modulation means 4 and then circulated by the dial signal discrimination means 5. It is discriminated as a time-series signal representing a group, or a circle, and the result of this discrimination is notified to the automatic call response circuit 3, where the content of the response message is changed in accordance with the combination of the PB signals. With such a device, even if the owner needs to change the response message while out, he or she can easily change it from an outside line, thereby ensuring that the optimal response message is always set. This allows accurate absence information to be conveyed to the caller.

[Problems with background technology]

However, in general, the fluctuation range of the signal level of the PB signal received by the dial signal demodulation means 4 is that the fluctuation range of the transmission signal level transmitted from the calling party is about 13 ci3, the line loss width is about 32 dB, and If a level fluctuation range of about 68 is taken into account, the number becomes 508 or more. On the other hand, the dial signal demodulating means 4 can be constructed of either an integrated circuit or a discrete circuit, and can only secure a dynamic range of T of 30 dB to 456 dB. Therefore, the arriving P
Depending on the signal level of the B signal, accurate demodulation may not be possible.
There is a drawback that the discrimination rate of the dial signal discrimination means 5 is lowered.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an answering machine that can always accurately discriminate a PB signal regardless of its received signal level, thereby increasing the discrimination rate and performing accurate remote control.

[Summary of the invention]

In order to achieve the above object, the present invention provides an automatic gain control means before the PB signal reception and demodulation means, and uses the automatic gain control means to suppress the received signal level of the PB signal so that it is within the dynamic range of the demodulation means. It was designed to fit in.

[Embodiments of the invention]

FIG. 1 shows the configuration of an answering machine according to an embodiment of the present invention. In this figure, the same parts as in FIG. 2 are given the same reference numerals and detailed explanations will be omitted.

An automatic gain adjustment (A
GO) circuit 8 is provided. This AGC circuit 8 is
It consists of an adjustment amplifier 80 and its control section, and this control section includes a first time constant circuit consisting of a resistor 81, a diode D, and a capacitor 82, and a resistor 83 and a capacitor 82.
A second time constant circuit is provided. These first and second time constant circuits are for setting an attack time until AGC operation is performed and a recovery time until AGC is restored, respectively.

With this configuration, when an incoming call signal arrives from the caller in the answering mode, this incoming signal is detected by the incoming call detecting section of the automatic call answering circuit 3, and as a result, a A preset response message is sent to the telephone line 6 from a certain voice generating circuit. Therefore, by listening to this response message, the caller can know that the owner is absent, as well as the reason, contact information, time to return home, etc.

On the other hand, in order for the owner to change contact information etc. from outside,
When a PB signal is sent by operating a predetermined dial button during sending of the response message or during a predetermined time after sending is completed, this PB signal is first sent to the AGC via the changeover switch 7.
The received signal level is guided to a circuit 8, and the received signal level is adjusted by this AGC circuit 8.

For example, if the above PB signal is sent after the response message has been sent, this PB signal has no other large signal components and has a high S/N, so the AGCqO
The AGC width of the line 8 is set to be less than the difference between the dynamic range of the dial signal demodulating means 4 and the maximum input width level of the PB signal arriving from the telephone line 6, and the attack time is set to within several tens of msec. By setting the time constant of the time constant circuit 1 in advance, the level of the PB signal is adjusted by the AGC circuit 8 and the dynamic range of the dial signal demodulating means 4 is adjusted regardless of the level of the received signal. Within the range. Therefore, the PB signal always satisfies II reliably, and the discrimination rate of the dial signal discrimination means 5, which discriminates the combination of PB signals from this demodulated output, is high.

Furthermore, when a PB signal is sent while a response message is being sent, the voice signal of the response message is superimposed on this PB signal, and the signal level of this voice signal is higher than that of the PB signal. The PB signal has a very degraded S/N ratio. Therefore, in order to detect the PB signal, it is necessary to perform demodulation during a period when the voice signal of the response message is interrupted or the signal level is low, and therefore the recovery time of the AGC circuit 8 is several tens of milliseconds.
The time constant of the second time constant circuit is set to be within ec. Then, AGC is applied to the PB signal during periods when the voice signal of the response message is interrupted or the signal level becomes low, and as a result, the level of the PB signal is adjusted no matter what the received level is, and the dial signal is demodulated. This will fall within the dynamic range of means 4. Therefore, even if a PB signal arrives during the sending period of this response message, the dial signal discriminating means 5 discriminates the PB signal with a high discrimination rate. By the way, without considering the recovery time, this time is, for example, several tens of meters.
If it is more than sec, it means that AGC is always working on the voice signal of the response message with a high average level, so AGC is almost not applied to the PB signal that needs to be detected during the period when the voice signal is interrupted. As a result, depending on the received signal level of the PB signal, the dynamic range of the dial signal demodulating means 4 is exceeded, leading to a decrease in the discrimination rate.

In this embodiment, the dial signal demodulating means 4
An AGC circuit 8 is provided at the front stage of the PB signal, and this AGC circuit 8 applies AGC to the received PB signal to suppress the signal level, so that no matter what level the PB signal arrives, the signal level can be dialed reliably. This can be kept within the dynamic range of the signal demodulating means 4, thereby allowing the dial signal discriminating means 5 to accurately discriminate the PB signal and improving the discrimination rate.

Moreover, in this embodiment, the AGC circuit 8 is provided with the first and second time constant circuits, and these circuits set the attack time and recovery time appropriately, so that even if the PB signal does not correspond to the response message, Even if the message arrives during transmission, AGO can be reliably applied without being affected by the voice signal of the response message, thereby allowing accurate discrimination. - Note that the present invention is not limited to the above embodiments. For example, the resistance 81.83 of each of the first and second time constant circuits
may each be configured with a variable resistor so that the attack time and recovery time can be varied. In addition, the circuit configuration of the AGC circuit, the configuration of the automatic call response circuit,
The details of the response operation controlled by the B signal can also be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

As detailed above, according to the present invention, automatic gain control means is provided before the PB signal reception and demodulation means, and the automatic gain control means suppresses the received signal level of the PB signal to within the dynamic range of the demodulation means. By making it possible to always accurately discriminate the PB signal regardless of the received signal level, it is possible to provide an answering machine that can improve the discrimination rate and perform accurate remote control.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the configuration of an answering machine according to an embodiment of the present invention, and FIG. 2 is a conventional answering machine 'I1.
FIG. 2 is a circuit block diagram showing the configuration of a talking device. 1... Incoming call circuit, 2... Dial call circuit, 3...
・Automatic call response circuit, 4... dial signal demodulation means,
5...Dial signal discrimination means, 6...Telephone line, 7
...Selector switch, 8...Automatic gain adjustment (AGC>
Circuit, 80...Adjustment amplifier, 81...Resistance of the first time constant circuit, 82...Capacitor, 83...Resistance of the second time constant circuit.

Claims (2)

[Claims] (1) In an answering machine equipped with a function of detecting a PB signal arriving via a line and controlling a response operation according to the detection result, the received signal level of the PB signal is 1. An answering machine characterized by being provided with automatic gain adjustment means for suppressing. (2) The answering machine according to claim (1), wherein the automatic gain adjustment means has first and second time constant circuits that respectively set predetermined attack and recovery times.