JPH02301351A - Telephone set with noise elimination function - Google Patents

Abstract

PURPOSE:To eliminate a noise signal in an excellent way by providing a noise eliminating circuit bringing a voice signal from a transmitter into an interrupt state or an attenuation state only when a signal level of any of the voice signal from the transmitter and the voice signal to a receiver is less than the set signal level. CONSTITUTION:Noise elimination circuits 3, 3' are respectively provided between a telephone set circuit 4 and a transmitter 2 and between the circuit 4 and a receiver 1, and noise is eliminated from the transmission voice signal from the transmitter 2 with the noise elimination circuit 3 and eliminated from the reception voice signal to the receiver 1 by the noise elimination circuit 3' as specified. When the result of comparison represents that the voice signal level is less than the set signal level, the voice signal is interrupted or attenuated by the comparison result. Moreover, when the voice signal is discriminated to be more than the specified signal level or over, the voice signal passes through as it is to eliminate noise automatically for the talking. Thus, the noise signal included in the voice signal is eliminated in an excellent way between calls.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for removing noise as a signal at a lower level than at least one of an audio signal to the other party and an audio signal from the other party. The present invention relates to a telephone with a noise reduction function.

[Conventional technology]

Generally, when a call is made with the other party via a telephone, various miscellaneous noises generated in the surrounding area are mixed into the transmitted audio signal as so-called noise.
Therefore, the reality is that it is difficult for the other party to hear and recognize the audio signal.

For this reason, a telephone equipped with a noise canceling function has been considered, as disclosed in Japanese Patent Application Laid-Open No. 55-86253. In addition to the transmitter, ambient noise is collected using a small microphone installed in the phone itself, and the noise signal from the transmitter is canceled out by the collected signals corresponding to the ambient noise. be.

[Problem to be solved by the invention]

However, in the case of a telephone equipped with a noise canceling function, there is a problem in that the noise is not canceled well, and in some cases, the transmitted audio signal is also canceled out. This is because the handset itself is used in various postures with an undefined distance from the main body of the phone, and therefore,
This is because the conditions for collecting ambient noise from small microphones and transmitters are not always the same, and as a result, noise signals from the transmitter are canceled out in an unbalanced manner. Additionally, if a call is made very close to the telephone, the transmitted voice will also be collected by a small microphone as ambient noise, and as a result, the transmitted voice signal from the handset will be greatly attenuated. be.

On the other hand, in conventional telephones, no particular consideration is given to noise signals contained in the voice signal from the other party. Although some consideration has been given to the removal of noise signals contained in transmitted audio signals, no consideration has been given to the removal of noise signals contained in received audio signals.

An object of the present invention is to provide a transmitting audio signal and a receiving audio signal,
The object of the present invention is to provide a telephone that can effectively remove noise signals contained in either one of the two.

[Means to solve the problem]

The above purpose is to cut off or attenuate at least one of the audio signals from the transmitter and the audio signal to the receiver only while the signal level is below the set signal level. This is achieved by providing a noise removal circuit to remove the noise.

[Effect]

The idea is to provide a noise removal circuit for the transmitted audio signal, the received audio signal, or both audio signals. Since noise signals are generally at a lower level than audio signals, it is recommended to cut off the overall signal or significantly attenuate the signal level only when the overall signal level is below the set signal level. For example, at least noise signals mixed in between calls are removed or their signal levels are significantly attenuated. Also, if the overall signal level is higher than the set signal level, and if the overall signal level is allowed to pass through as is, the audio signal will be transmitted to the other party with a high S/N ratio, and the voice signal will be transmitted to the other party with a high S/N ratio. It can be played back as audio.

〔Example〕

Hereinafter, the present invention will be explained with reference to the accompanying drawings.

The figure shows a block configuration of an example of a telephone according to the present invention. In general, a telephone set consists of a receiver 1, a transmitter 2, and a telephone circuit 4 (consisting of hook switches, bells, coils, resistors, capacitors, etc. other than the receiver 1 and the transmitter 2). It consists of a handset and a telephone body. A handset 2 and a receiver 1 are built into the handset, and a telephone circuit 4 is built into the telephone body.

Now, as shown in the figure, the telephone in this example is provided with noise removal circuits 3 and 3' between the telephone circuit 4, the transmitter 2, and the receiver L, respectively, so that the transmitted voice 16 from the transmitter 2 is The received voice signal to the receiver 1 is subjected to a predetermined noise removal by a noise removal circuit 3'.

That is, the noise removal circuits 3.3' have substantially the same characteristics and the same configuration, and are constructed using an analog comparator, an analog switch, an analog comparator, an analog selector, and an attenuator as elements. In the off-hook state, the audio signal level and the set signal level are constantly compared in each of the noise removal circuits 3 and 3', but if a comparison result indicating that the audio signal level is below the set signal level is obtained. In some cases, the result of this comparison is used to block or attenuate the audio signal. Furthermore, if it is determined that the signal level is higher than the set signal level, the audio signal is passed through as is, so that noise removal is automatically performed between calls.

In this case, the setting signal level for each of the noise removal circuits 3 and 3' can be set arbitrarily from the outside, so that noise removal is performed according to the surrounding noise. In particular, the noise removal circuit 3'
It has become essential for. This is because it is necessary to hear a dial tone when making a call, and at that time -
This is because the crossing setting signal level must be set low. It is sufficient that the noise removal circuit 3, 3' and the setting mechanism for setting the set signal level from the outside are appropriately provided in the telephone body or in the transmitter/receiver.

Although the present invention has been explained above, the noise removal circuits 3, 3
A telephone equipped with any one of the following is also considered to be a telephone according to the present invention, but its operation is clear from the above explanation and does not require any particular explanation.

Furthermore, the noise removal circuit and method according to the present invention can be applied to audio signals other than audio signals from telephones, and even to non-audio signals.

〔Effect of the invention〕

As explained above, according to the present invention, noise signals contained in voice signals are effectively removed between calls.

[Brief explanation of drawings]

The figure is a diagram showing the configuration of an example of a telephone according to the present invention. 1... Receiver, 2... Transmitter, 3.3'... Noise removal circuit, 4... Telephone circuit. Patent applicant Hitachi Communication Systems Co., Ltd. Agent Patent attorney Masami Akimoto (1 other person)

Claims (1)

[Scope of Claims] 1. A telephone for transmitting and receiving voice signals to and from the other party, which includes at least one of the voice signals from the transmitter and the voice signal to the receiver; A telephone with a noise removal function, which is equipped with a noise removal circuit for cutting off or attenuating the audio signal only while the signal level is below a set signal level. 2. The signal level can be set arbitrarily from the outside.
The telephone with a noise removal function according to claim 1.