JPH01215167A - Telephone set - Google Patents

Abstract

PURPOSE:To attain always clear talking by keeping always the sound pressure level difference between an incoming voice signal and a side tone constant and giving the result to a receiver. CONSTITUTION:A transmission voice signal (f) inputted from a transmitter 10 is given to a telephone circuit 30, outputted from a subscriber line 50, a side tone (b) is outputted from the telephone circuit 30 at the same time and inputted to a difference detection circuit 41. The difference detection circuit 41 detects the sound pressure level difference between the incoming voice signal (a) and the side tone (b) inputted from the subscriber line 50 and outputted from the circuit 30 and gives an output it to an amplifier circuit 42 as a sound pressure level difference signal (c). The amplifier circuit 42 based on the sound pressure level difference signal (c) amplifies the incoming voice signal (a) to a prescribed sound pressure level and outputs an amplification incoming voice signal (d) to a voice mixing circuit 43. The voice mixing circuit 43 mixes the side tone (b) and the amplified incoming voice signal (d) and gives an output to the receiver 20 as the received voice signal (e). Thus, communication being always clear is attained.

Description

[Detailed description of the invention] [Industrial application field] The present invention is utilized in the field of telephone communications.

The present invention relates to a telephone set, and more particularly to a telephone set that uses side sound as a reference and maintains a constant difference in sound pressure level between the side sound and an incoming voice signal.

〔overview〕

The present invention enables a telephone set to maintain a constant sound pressure level difference between an incoming voice signal and sidetone and input it to the receiver, thereby enabling clear communication at all times.

[Conventional technology]

In a conventional telephone, the sound pressure level of an incoming voice signal is
It is independent of the side sound pressure level of the outgoing voice signal, and the sound pressure of the incoming voice signal is amplified manually using an amplification circuit built into the telephone circuit, or by a fixed amplification factor. It was configured.

[Problem that the invention seeks to solve]

The conventional telephones described above amplify the sound pressure of the incoming voice signal using an amplifier circuit built into the telephone circuit at a fixed or manually variable amplification factor, and amplify the sound pressure of the incoming voice signal regardless of the side sound pressure level of the outgoing voice signal. Therefore, the sound pressure level of the incoming voice signal depends on the sound pressure level of the voice signal input via the telephone line, and if the sound pressure level of the voice signal input manually via the telephone line is low, , the sound pressure level of the voice emitted from the handset (in the present invention, the handset includes a receiving means such as a speaker) is lowered,
There was a drawback that the incoming voice was difficult to interrupt.

In addition, since the speaker speaks to the receiver on the premise that the speaker's voice is generated from the receiver's receiver at an appropriate sound pressure level, the speaker's microphone (in the present invention) (The transmitter shall include a transmitting means such as a microphone.) When the sound pressure level of the human input voice and the sound pressure level of the voice emitted from the receiver's handset differ due to the influence of the transmission route, etc. However, since the sound level cannot be balanced between the receiver and the sender, there is a risk that the receiver may misunderstand the content of the call.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone set which eliminates the above-mentioned drawbacks and allows clear calls at all times by keeping the sound pressure level difference between the incoming voice signal and the sidetone constant.

[Means for Solving the Problems] The present invention provides a telephone set including a handset and a telephone circuit.
The method further includes a sidetone mixing circuit that mixes an incoming voice signal output from the telephone circuit and sidetone while maintaining a constant sound pressure level difference between the sidetone and the incoming voice signal, and outputs the mixture to the receiver. Features.

[Effect]

The sidetone mixing circuit detects, for example, a sound pressure level difference between the incoming audio signal and the sidetone, amplifies the incoming audio signal so that this sound pressure level difference is always constant, and The incoming voice signal and the sidetone are mixed and output to the receiver.

Therefore, the sound pressure level difference between the incoming voice signal and the sidetone is always kept constant and input to the receiver, making it possible to always have a clear conversation.

〔Example〕

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

The figure is a block diagram showing one embodiment of the present invention.

This embodiment includes a transmitter 10, a receiver 20, and a telephone circuit 3.
0, the incoming voice signal a is input from the subscriber line 50 and output from the telephone circuit 30, and the outgoing voice signal f is input from the transmitter 10 and output from the telephone circuit 30. A sidetone mixing circuit 40 is provided which mixes the sidetone sound with a constant sound pressure level difference between the sidetone sound and the incoming voice signal a, and outputs the mixture to the receiver 20.

The sidetone mixing circuit 40 is connected to a difference detection circuit 41 that detects the sound pressure level difference between the incoming audio signal a and the sidetone sound signal and outputs a sound pressure level difference signal C; An amplifier circuit 42 that amplifies the input incoming voice signal a and outputs the amplified incoming voice signal d so that the sound pressure level difference between the voice signal a and the side sound becomes a predetermined constant sound pressure level difference. and an audio mixing circuit 43 that mixes the output amplified incoming audio signal d and the sidetone and outputs it to the receiver 20 as a received audio signal e.

A feature of the present invention is that in the figure, a sidetone mixing circuit 4 including a difference detection circuit 41, an amplification circuit 42, and an audio mixing circuit 43 is shown.
The reason is that 0 is set.

Next, the operation of this embodiment will be explained.

A transmitted voice signal f manually input from the transmitter 10 is input to the telephone circuit 30 and output from the subscriber line 50. At the same time, sidetone is output from the telephone circuit 30 and input to the difference detection circuit 41. The difference detection circuit 41 is connected to the subscriber line 5.
0 and output from the telephone circuit 30 and the side sound signal A is detected and output as a sound pressure level difference signal C to the amplifier circuit 42. The amplification circuit 42 amplifies the incoming audio signal a to a predetermined sound pressure level based on the sound pressure level difference signal C, and outputs the amplified incoming audio signal d.
is output to the audio mixing circuit 43. Audio mixing circuit 4
3, the sidetone and the amplified incoming voice signal d are mixed and outputted to the receiver 20 as a received voice signal e.

〔Effect of the invention〕

As explained above, the present invention improves the sound pressure of the voice input manually from the telephone line by making the difference in the sound pressure level between the side sound pressure level of the outgoing voice and the incoming voice signal always constant. It is possible to maintain a constant incoming voice sound pressure level without being affected by the level, and it is not affected by the drop in sound pressure on the voice signal transmission path, allowing accurate, stable and clear calls at all times. It has the effect of

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Transmitter, 20... Receiver, 30... Telephone circuit, 40... Sidetone mixing circuit, 41... Difference detection circuit, 42... Amplification circuit, 43... Audio Mixed circuit, 5
0...Subscriber line, a...Incoming voice signal, b...
Sidetone, C: sound pressure level difference signal, d: amplified incoming voice signal, e: received voice signal, f: transmitted voice signal. Patent Applicant: NEC Corporation 6, Agent: Patent Attorney Naotaka Ide Structure of the Example

Claims (1)

[Claims] 1. In a telephone including a handset (20) and a telephone circuit (30), an incoming voice signal (a) output from the telephone circuit and a sidetone (b) are combined into the sidetone and the telephone circuit. A telephone set comprising a sidetone mixing circuit (40) for mixing an incoming voice signal with a constant sound pressure level difference and outputting the mixed signal to the receiver.