JPH0440142A - Telephone set with automatic volume control - Google Patents

Abstract

PURPOSE:To keep voice so as to easily listen to it while extremely changing the back ground noise of a telephone set by providing a microphone at the telephone set so as to measure the back ground noise, and controlling gain to a back ground noise level by a speech network block. CONSTITUTION:A comparator 5 excludes the output of a transmission microphone 4 (the voice component of a speaker) from the output of a back ground noise measuring microphone 6 and outputs a true back ground noise level. When the output voltage is enlarged, the gain control resistance of a gain control reception amplifier is enlarged as well and the output of the gain control reception amplifier is enlarged. On the other hand, when the output of the comparator 5 is reduced, the gain control resistance is reduced as well, and the output of the gain control reception amplifier is also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a telephone, and more particularly to a telephone having an automatic volume control function.

[Conventional technology]

Conventionally, as shown in FIG.
The output obtained by dividing the output of the transmitting amplifier 2 with a resistor is connected to the side tone input of the receiving amplifier circuit 8, and the output of the receiving amplifier circuit 8 is connected to the receiving speaker 3, and the output of the transmitting amplifier 2 A telephone set using a speech network block in which the input is connected to a transmitting microphone 4 is known.

[Problem to be solved by the invention]

With conventional telephones, when the level of background noise (environmental noise from the telephone) increases when you are making a call inside a station or on the side of the road, the output from the telephone's earpiece speaker is affected by the background noise. This has the disadvantage that it becomes difficult to hear the other party's voice because of cancellation.

Therefore, in order to solve these conventional drawbacks, this invention increases the output level of the telephone receiver speaker when the background noise level of the telephone increases. The aim is to provide a telephone that is easy to hear even in the middle of the day.

[Means to solve the problem]

In order to alleviate the above problems, the present invention provides a telephone with a background noise measurement microphone for measuring the background noise level, and a speech network block that includes a background noise measurement microphone for measuring the background noise level. The speaker's voice component is removed from the output of the speaker to extract the true background noise level, and the gain of the receiving amplifier is controlled by the level output. We have made it possible to obtain a telephone that is easy to hear even in the middle of the day.

[Effect]

In a phone using the speech network block configured as described above, if hack ground noise becomes high while talking on the phone, the output level of the background noise measurement microphone increases, Correspondingly, the gain of the receiving amplifier increases. In addition, if the background noise measuring microphone picks up changes in the level of the speaker's voice, the receiver amplifier's gain
Since the speaker's audio signal is removed before the control, it does not affect the output level of the receiver speaker.

This effect reduces true background noise.
According to the level, the output level of the telephone receiver speaker can be controlled for easy listening.

(Example〕 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the speech network block has a terminating transformer 7 connected to the input of a gain-controlled receiving amplifier 1 with a side tone input and the output of a transmitting amplifier 2. The output voltage divided by the resistor is connected to the side tone input of the gain control receiver amplifier circuit 1, the output of the gain control receiver amplifier circuit 1 is connected to the receiver speaker 3, and the input of the transmitter amplifier circuit 2 is connected to the transmitter speaker 3. The output of the transmitting microphone 4 and the output of the background noise measurement micro are connected to the input of the comparator 5, and the output of the comparator 5 is connected to the gain
The configuration is such that it is connected to the gain control input of the control receiver amplifier 1.

When the speech network block of the telephone is configured in this way, the comparator 5 removes the output of the transmitting microphone 4 (the speaker's voice component) from the output of the background noise measuring micro, and produces a true hack. ground noise
Output the level.

As the output voltage increases, the gain control resistance of the gain-controlled receiver amplifier also increases, and the output of the gain-controlled receiver amplifier increases. Furthermore, as the output of the comparator 5 becomes smaller, the gain control resistance also becomes smaller, and the output of the gain control receiver amplifier also becomes smaller.

In the embodiment described above, correction is made so that the audio signal of the speaker included in the input signal of the background noise measurement micro and the audio signal of the input signal of the transmitting microphone 4 are electrically aligned in phase. It is necessary to install a circuit and adjust the position of the background noise measurement microphone on the telephone.

Although not particularly shown, the existing ringer block and dialer block perform the above-mentioned speech
Connected in parallel with network blocks.

〔Effect of the invention〕

As explained above, this invention is a simple method in which a telephone is equipped with a microphone that measures background noise, and a speech network block uses a receiving amplifier that controls the gain with respect to the background noise level. This configuration has the effect of keeping the audio output of the receiving speaker easy to listen to without being canceled out by the background noise, even when the background noise of the telephone changes drastically, such as in a station premises.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a speech network block of a telephone with automatic volume control according to the present invention;
1 is a block diagram of a conventional telephone speech network block. - Gain control receiving amplifier - Transmitting amplifier - Receiving speaker - Transmitting microphone - Comparator - Background ground noise measurement microphone - Termination transformer - Receiving amplifier and above Applicant: Seiko Electronics Co., Ltd. Agent Patent attorney Takayuki Hayashi Supplementary Figure 1 Figure 7

Claims (1)

[Claims] In a telephone set including a speech network block, a ringer block, and a dialer block, the speech network block includes a background noise measuring microphone, a transmitting microphone, and a receiving speaker,・Comprised of a comparator that removes the audio input of the transmitting microphone from the noise measurement microphone input, a receiving amplifier whose gain is variable for its output, and a transmitting amplifier that amplifies the audio input of the transmitting microphone. A telephone with automatic volume control.