JPH056820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic transmission/reception level adjustment circuit for automatically adjusting the transmission/reception level of a telephone or the like based on a comparison of the transmission/reception level.

[Prior Art] Generally _, a telephone is configured as shown in _FIG . It constitutes a transmitting/receiving switching circuit that receives the received voice signal and sends the transmitted voice signal to the telephone exchange.

A transmitting signal from the transmitting microphone 6 of the handset 4 is applied to the speech network 2 via an amplifier 8 on the transmitting side, and a receiving signal from the speech network 2 is applied to the receiving side. The signal is applied to the receiver speaker 12 of the transmitter/receiver 4 via the amplifier 10 .

[Problem that the invention seeks to solve]

Conventionally, when making a call using such a telephone, when the call distance is long or the noise level is high, the receiving signal level from the other party's telephone is low and sufficient intelligibility cannot be obtained. In this case, the user psychologically becomes under the illusion that the level of the signal reaching the other person is low, and tries to raise the level of understanding by shouting louder.
Also, on the other side, the receiving level increases due to the loud voice of the sender, so there is an illusion that the intelligibility of the other side will not deteriorate even if the voice is lowered, and the voice tends to become even softer. It is known from experience that it becomes increasingly difficult to make phone calls.

This is due to the illusion that there is a direct relationship between your own listening level and the listening level of the other party's phone, and such unevenness in the sending and receiving levels interferes with normal communication. It was becoming the cause.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic transmitting/receiving level adjustment circuit that normalizes the call state by adjusting the level between transmitting and receiving levels.

[Means for solving problems]

The automatic transmitting/receiving level adjustment circuit of the present invention includes a first amplifier (buffer amplifier 18) that takes out the transmitting signal from the transmitting system 14, and a second amplifier (buffer amplifier 20) that takes out the receiving signal from the receiving system 16. ), a level difference detecting means (level comparator 22) for receiving the transmitting signal from the first amplifier and the receiving signal from the second amplifier and detecting a level difference between the two; and this level difference detecting means. a control signal generation circuit 24 that generates a level control signal in response to a level difference signal generated by the transmitter; a first electronic volume circuit 26 that adjusts the level of the received signal; and a second electronic volume circuit 26 that is installed in the receiving side system and that adjusts the level of the received signal in response to the level control signal generated by the control signal generation circuit. It is characterized by comprising a circuit 28.

[Effect]

Therefore, the present invention compares the transmitting signal level and the receiving signal level to detect the level difference between the two signals, and when the receiving signal level is small, reduces the transmitting signal level in accordance with the level difference. The receiving signal level is largely adjusted, and when the receiving signal level is high, the receiving signal level is reduced in accordance with the level difference, and the transmitting signal level is greatly adjusted.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the automatic transmission/reception level adjustment circuit of the present invention, and the same parts as those of the telephone shown in FIG. 4 are given the same reference numerals.

In FIG. 1, a transmitting signal from a transmitting system 14 on the output side of the transmitting microphone 6 of the handset 4 and a receiving system 1 on the output side of the amplifier 10 are shown.
The reception signal from 6 is applied via buffer amplifiers 18 and 20 as first and second amplifiers to a level comparator 22 as a level difference detection means for detecting the level difference between both signals.

The level difference detection signal generated by the level comparator 22 is applied to a control signal generation circuit 24 that generates a level control signal according to the level difference signal.
The level control signal generated by this control signal generation circuit 24 is transmitted to a first electronic volume circuit 26 installed in the transmitting side system 14 as a level adjusting means on the transmitting side for adjusting the signal level, and a receiving side as a level adjusting means on the receiving side. They are respectively added to a second electronic volume circuit 28 installed in the side system 16.

The electronic volume circuit 26 adjusts the level of the transmitting signal passing through the transmitting system 14 based on the level control signal, and the electronic volume circuit 28 adjusts the level of the receiving signal passing through the receiving system 16. The adjustment is performed based on a control signal, and the level adjustment relationship between the two is controlled so that they are inversely related to each other.

The operation will be explained based on the above configuration.

The receiving signal level appearing in the receiving side system 16 at the output side of the amplifier 10 from the speech network 2 is _VRIN , the level of the reproduced receiving signal applied to the speaker 12 is VRO, the transmitting signal level of the microphone 6 is V _TIN , and the transmitting signal level is V _RIN . The level of the outgoing voice signal appearing at the input side of the amplifier 8 of the side system 14 is assumed to be V _TO .

The receiving signal level V _RIN and the transmitting signal level V _TIN are determined by buffer amplifiers 18 and 20, respectively.
The signal is applied to the level comparator 22 via the signal, and the level difference between the two signals ±ΔV is determined.

In this case, if the receive signal level V _RIN is smaller than the transmit signal level V _TIN (V _RIN < V _TIN ), its polarity is positive (+), and if the relationship between these signal levels is reversed ( When V _RIN > V _TIN ), the polarity shall be negative (-).

Therefore, the receiving signal level V _RIN is equal to the transmitting signal level.
If it is smaller than V _TIN (V _RIN < V _TIN ),
Signal level difference detected by level comparator 22 +
ΔV is applied to the control signal generation circuit 24, and the reception signal level is output from the control signal generation circuit 24 to the electronic volume circuit 28 according to the signal level difference +ΔV.
A level control signal V _RC that increases V _RIN is applied, and a level control signal V _TC that decreases the transmitting signal level V _TIN in accordance with the signal level difference +ΔV is applied. In this case, the internal impedances of the electronic volume circuits 26 and 28 are adjusted to amplify the reproduced reception signal level V _RO and reduce the transmitted transmission signal level V _TO .

As a result, the sound reproduced from the speaker 12 becomes louder, and the outgoing voice signal level V _TO to the other party's telephone is reduced. As a result, the other party's voice becomes psychologically louder due to the lower reception level.
The received signal level V _RIN increases.

In this case, as the receiving signal level V _RIN increases, the signal level difference between it and the transmitting signal level V _TIN decreases accordingly, so the level amplification factors of the electronic volume circuits 26 and 28 are controlled, and the specific transmitting/receiving equilibrium at the number level.

Further, when the transmitting signal level V _TIN is smaller than the receiving signal level V _RIN (V _RIN > V _TIN ), the signal level difference -ΔV is applied from the level comparator 22 to the control signal generating circuit 24 . , a level control signal V RC is applied from the control signal generation circuit 24 to the electronic volume circuit 28 in accordance with the signal level difference _-ΔV , and a level control signal V _RC is applied to the electronic volume circuit 28 in accordance with the signal level difference -ΔV. Level control signal V _TC that increases the speech signal level V _TIN
is added. At this time, electronic volume circuit 2
The internal impedances of 6 and 28 are adjusted to reduce the reproduced received signal level V _RO and amplify the transmitted transmitted signal level V _TO .

As a result, the sound reproduced from the speaker 12 becomes lower, and the outgoing voice signal level V _TO to the other party's telephone is amplified. As a result, the voice of the other party becomes psychologically lower due to the increase in the listening level, and the received voice signal becomes lower. Level V _RIN becomes smaller.

In this case, as the receiving signal level V _RIN decreases, the signal level difference between it and the transmitting signal level V _TIN decreases accordingly, so the level amplification factors of the electronic volume circuits 26 and 28 are controlled, and the specific transmitting/receiving Balance is achieved at the number level.

FIG. 2 shows the output characteristics of the reproduced reception signal level V _RO with respect to the transmission signal level V _TIN , and the reproduction reception signal level V _RO increases or decreases linearly in accordance with the transmission signal level V _TIN .

Further, FIG. 3 shows the output characteristics of the transmitted voice signal level V _TO with respect to the received voice signal level V _RIN , and the transmitted voice signal level V _TO increases or decreases linearly in accordance with the received voice signal level V _RIN .

As is clear from these output characteristics, the receiving side adjusts the transmitting/receiving level regardless of the received signal level from the other party's phone. In addition, by reducing the transmitting signal level, you can automatically perform operations such as raising your voice to the other party.
When the receiving signal level is high, there is no need to consciously raise the voice to improve intelligibility, and when the voice level from the other party is high, the transmitting signal level to the other party can be increased. This allows you to automatically perform operations such as suppressing the audio to the other party. As a result, a constant received voice level is maintained and a good call condition is obtained.

In this embodiment, electronic volume circuits 26 and 28 are installed as level adjustment means, but a variable gain amplifier or the like whose amplification gain is adjusted based on a level control signal may also be used.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

(a) Detects the level difference in the received signal level, and if the other party's voice is low, the received signal level is amplified and raised, and the transmitted signal level is suppressed to make the other party's voice louder. , when the voice from the other party is loud, the level of the transmission signal to the other party is increased, so by reaching an equilibrium state at a specific transmission and reception signal level, a good communication condition is obtained and the intelligibility is improved. can be increased.

(b) Even if the other party is speaking loudly enough, the received signal level may be low due to line conditions, etc.
Even when sufficient intelligibility cannot be obtained, the receiving side can make the voice from the other party louder by amplifying the received signal level, thereby increasing intelligibility.

(c) When the automatic transmission/reception level adjustment circuit of this invention is installed in both telephones, the signal level control of the telephones will be linked to each other,
A stable and highly intelligible conversation can be maintained regardless of the distance of the telephone line.

(d) Since the transmitting signal is extracted from the transmitting system through the first amplifier, and the receiving signal is extracted from the receiving system through the second amplifier, the influence on each system by adjusting the transmitting and receiving levels can be controlled.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the automatic transmission/reception level adjustment circuit of the present invention, Figs. 2 and 3 are explanatory diagrams showing output characteristics in level adjustment control, and Fig. 4 shows the configuration of a conventional telephone set. FIG. 14...Sending side system, 16...Receiving side system, 1
8... Buffer amplifier (first amplifier), 20...
... Buffer amplifier (second amplifier), 22 ... Level comparator (level difference detection means), 24 ... Control signal generation circuit, 26 ... First electronic volume circuit, 28 ... Second electronic volume circuit .

Claims (1)

[Claims] 1. A first amplifier that extracts a transmitting signal from a transmitting system, a second amplifier that extracts a receiving signal from a receiving system, and a second amplifier that extracts a receiving signal from a receiving system; 2
a level difference detection means for receiving the reception signal from the amplifier of the receiver and detecting a level difference between the two; a control signal generation circuit for generating a level control signal in accordance with a level difference signal generated by the level difference detection means; a first electronic volume circuit installed in the speaking side system to adjust the level of the transmitting signal in response to the level control signal generated by the control signal generating circuit; and a first electronic volume circuit installed in the receiving side system to adjust the level of the transmitting signal; An automatic transmitting/receiving level adjustment circuit comprising: a second electronic volume circuit that adjusts the level of the received signal in response to the level control signal generated by the generation circuit.