JPH01212950A - Telephone system - Google Patents

Abstract

PURPOSE:To smoothly switch transmission and reception at the time of the occurrence of an ambient noise by switching the transmission and the reception by using speech sending signal with a non-linear characteristic. CONSTITUTION:A non-linearization circuit 20 to give non-linearity to a voice signal is provided between an amplifier 10 and an attenuator 11, and the output of an inverter 17 is impressed directly to the terminal C of the attenuator 4. The voice signal amplified by the amplifier 10 is impressed to the non- linearization circuit 20. Thus, as the level of the output signal of the amplifier 10 becomes larger, a speech sending level is suppressed, and it comes into a constant state from a certain level. The output signal of this non-linearization circuit 20 is impressed to a control circuit 16. When a large receiving signal is inputted from a line in case of the suppressed state of the speech sending level, the system is switched into a reception prior state, and the output sound volume of a speaker 8 is raised, and communication for which the obstruction of the ambient noise is reduced becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a telephone device that is capable of making calls without using a handset using a microphone and speaker provided on the telephone body.

Prior Art FIG. 3 is a block diagram showing the configuration of a conventional telephone device (speakerphone).

In FIG. 3, 1 is a terminal Ls for connecting to a telephone line.

Balance network (BN) connected to L, 2 is an amplifier connected to balance network 1 to amplify the reception signal, 3 is a capacitor for direct current isolation between amplifier 2 and the subsequent stage, 4 is connected to capacitor 3 This is an attenuator that attenuates the received signal given by the receiver. 5 is a volume for adjusting the output signal of attenuator 4 to a predetermined level;
An amplifier 7 for amplifying the signal applied via the volume 5 is a capacitor that separates the amplifier 6 from the subsequent stage in terms of direct current, and a speaker 8 is connected to the capacitor 7.

9 is a microphone (hereinafter referred to as microphone 5), 10 is an amplifier that amplifies the output signal of the microphone 9, 11 is an attenuator that attenuates the output signal of the amplifier 10, and 12 is an attenuator that allows only a predetermined frequency range of the output signal of the attenuator 11 to pass through. This is a filter that supplies the balance network 1 to the balance network 1.

13 is an amplifier that amplifies the reception signal from capacitor 3;
14 is a capacitor connected to the output of filter 12;
5 is an amplifier that amplifies the signal applied through the capacitor 14; 16 is a control circuit whose output is set to 'H' level when the output level of the amplifier 15 is higher than the output level of the amplifier 13; 17 is the output of the control circuit 16 an inverter that inverts and outputs the signal; 18 a level detector that sets the output to ``H#'' level when the output signal of the amplifier 6 exceeds a predetermined value;
Reference numeral 19 denotes an OR circuit for calculating the logical sum of the output of the level detector 18 and the output of the inverter 17.

Next, the operation of the telephone device with the above configuration will be explained.

In a talking state, a received signal from the line is separated by the balance network 1, then amplified by the amplifiers 2 and 6, and output from the speaker 8. On the other hand, one's own voice is captured by a microphone 9, amplified by an amplifier 10, and then supplied to a balance network 1 via a filter 12.
Furthermore, it is sent out to the line. Therefore, as long as the line is connected, it is possible to talk to the other party without using a handset.

The received signal and the transmitted signal are individually amplified and outputted by an amplifier 13 and an amplifier 15, respectively, and a control circuit 16 compares the level relationship between their outputs. Control circuit 1
6 sets the output to @H# level and increases the attenuation amount of the attenuator 11 when the transmit signal is larger than the receive signal (at this time, the control (C) terminal of the attenuator 4 is connected to the OR circuit 19. (Since the output ``''L# level voltage is applied, the attenuation of the attenuator 4 is in a decreasing state.) As a result, the relationship between the received signal and the transmitted signal is
As shown in the figure, it is in the transmitting area divided by the broken line characteristics.

Next, when the receiving signal is larger than the transmitting signal, the output of the control circuit 16 is set to 'L' level, and the C of the attenuator 11 is
When the 'L' level voltage is applied to the terminal and the output of the inverter 17 becomes @H# level, the C terminal of the attenuator 4 is set at the '''H#H# level. Therefore, the output of the level detector 18 becomes @H# level. ``'' Even at the L#L# level, the attenuation amount of the attenuator 4 is set to be large, and conversely, the attenuation amount of the attenuator 11 is set to be small.
It operates in the receiving area divided by the solid line characteristics in the figure. Furthermore,
When the reception signal exceeds the level (for example, 0 point in FIG. 4), the level detector 18 operates and its output becomes @H" level. Therefore, the output of the inverter 17 becomes 1L".
Even if the level is high, the output of the OR circuit 19 is not at the @H# level, and the attenuation amount of the attenuator 4 is large, so that it is placed in the receiving range.

In this way, the signal levels of the received signal and the transmitted signal can be optimally set according to the levels of the received signal and the transmitted signal, thereby making it possible to conduct a telephone conversation that is compatible with the installation atmosphere without causing howling or the like.

Problems to be Solved by the Invention However, in the conventional configuration as described above, since the switching characteristics by the control circuit are as shown in Fig. 4, the reception level that occurs when the ambient noise etc. is large and the transmission level is high. When a signal is input, there is a problem that switching by the control circuit cannot be performed smoothly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone device that can smoothly switch to a receiving area operation in response to input of a receiving signal of a level equal to or higher when the transmitting level is high.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a voice transmitting means that performs processing such as amplification and non-linearization on an audio signal captured by a microphone and transmits it to a line, and a voice receiving means from the line. a receiving means for performing processing such as amplification on a signal and outputting it from a speaker; and an attenuation means provided in the middle of each signal path of the receiving means and the above-mentioned transmitting means and capable of attenuating the received signal and the transmitted signal. , comparing the levels of the received signal obtained from each of the receiving means and the transmitting means and the non-linearized transmitting signal, and varying the amount of attenuation of the attenuating means according to the magnitude relationship; The system is equipped with a control means for controlling.

Effects The present invention has the following effects due to the above structure. In other words, by providing non-linearity to the transmitting signal, a non-linearized transmitting signal can be used when comparing the level with the received signal, and even when ambient noise is large, the transmitting signal has a low level. It is compared as a signal, and is switched between transmission and reception in accordance with the reception signal. Therefore, switching between transmission and reception can be performed smoothly without being affected by ambient noise, etc., and the automatic reception state can be maintained.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a telephone device in one embodiment of the present invention.

In this embodiment, the same parts as in the conventional example shown in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted, and the different configuration will be explained. The features of this embodiment are as follows:
A nonlinearization circuit 20 is provided between the amplifier 10 and the attenuator 11 to impart nonlinearity to the audio signal, and the capacitor 14, level detector 18, and OR circuit 19 are removed. Note that the output of the inverter 17 is directly applied to the C terminal of the attenuator 4.

In the non-linearization circuit 20, 21 is a varistor connected to the output terminal of the amplifier 10, 22 is a capacitor provided between the varistor 21 and the ground, 23 is a resistor connected to the output terminal of the amplifier 10, and 24 is a resistor 23. A resistor connected to the other end, 25 a capacitor connected between the resistor 24 and the ground, 26 a resistor connected between the connection point of the resistors 23 and 24 and the C terminal of the attenuator 11, 27 the output side of the resistor 26 A capacitor 28 is a resistor connected between the output side of the capacitor 27 and the non-inverting terminal of the control circuit 16.

Next, the operation of the nonlinearization circuit 20 of the above embodiment will be explained.

The audio signal amplified by the amplifier 10 is applied to the non-linearization circuit 20. The applied audio signal is applied to the varistor 21, which is a non-linear element, and the resistor 2, depending on its level.
3.24. Capacitor 25. The output waveform is distorted by the filter circuit consisting of the resistor 26, and its change becomes non-linear as shown in FIG. Therefore, amplifier 10
As the level of the output signal increases, the transmission level is suppressed, and from this level onwards, it becomes constant. The output signal of this nonlinearization circuit 20 (having the characteristics shown in FIG. 2) is
It is applied to the control circuit 16 instead of the output of the conventional amplifier 15.

If a large reception signal is input from the line while the transmission level is suppressed, the reception signal level at the input terminal of the control circuit 16 will be higher than the transmission signal level, and the output of the control circuit 16 will be goes to the "L" level, and the "L#L#" level voltage is applied to the C terminal of the attenuator 11, and the "H" level voltage inverted and outputted by the inverter 17 is applied to the C terminal of the attenuator 4. Therefore, priority is given to receiving calls, the output foreground of the speaker 8 is enhanced, and a call can be made with reduced interference from ambient noise.

As described above, in this embodiment, even if the transmitting signal is at or above the level, when a receiving signal at or above the level is input, the non-linearization circuit 20 is provided in the transmitting system. Since this output signal is used for level comparison, it is possible to automatically hold the call.

Effects of the Invention As described above, according to the present invention, transmission and reception switching is performed using a transmission signal with non-linear characteristics.
It is possible to smoothly switch between sending and receiving when ambient noise occurs, making it easier to hear the other party's voice, and improving the call situation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a telephone device according to an embodiment of the present invention, FIG. 2 is a transmitting output characteristic diagram of the present invention, FIG. 3 is a block diagram of a conventional telephone device, and FIG. 4 is a transmitting output characteristic diagram of the telephone device. FIG. 3 is a diagram of reception switching characteristics. 1... Balance network, 2. 6.10.13
...Amplifier, 4.11...Attenuator, 8...
Speaker, 9...Microphone, 16...Control circuit, 17...Inverter, 20...Non-linearization circuit, 2
1...Varistor, 22.25...Capacitor, 23
．． 24.26...Resistance. Name of agent Patent attorney Satoshi Nakao and one other person Figure 2 My 7 Human power 8 y Figure 4

Claims (1)

[Claims] A voice transmitter that performs processing such as amplification and nonlinearization on the audio signal captured by the microphone and sends it out to the line; a voice receiver that performs processing such as amplification on the voice signal received from the line and outputs it from the speaker; and this sign language. an attenuating means provided in the middle of each signal path of the transmitting means and the transmitting means and capable of attenuating the received signal and the transmitting signal; 1. A telephone device comprising control means for comparing the level of the linearized transmission signal and varying the amount of attenuation of the attenuation means in accordance with the magnitude relationship.