JPH05300550A - Intra-band signal tranmitting device - Google Patents

Abstract

PURPOSE:To suppress the noises produced on a receiver circuit without attenuating the signaling intra-band signal. CONSTITUTION:An intra-band signal transmitting device 3 contains a noise detector 17 which detects the noises out of the signals received from a receiving point 13. Then a noise suppressing received signal attenuator 18 is provided at the next stage of a signaling intra-band signal cutting filter 21 and controlled by the detector 17. Thus the noises detected by the detector 17 are suppressed by the attenuator 18 and the noiseless signals are transmitted to a telephone receiver line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a transmission line for transmitting an analog speech signal as a dedicated line and uses a single frequency signal or a plurality of frequency signals within a band to perform signaling for a switch or a telephone. The present invention relates to an in-band signal transmission device in a dial system.

[0002]

2. Description of the Related Art As a signal transmission / reception system between telephones, a general telephone line and a dedicated line may be used. When using a general telephone line, an exchange and a transmission device are prepared in the telephone company, and as a method for transmitting a dial signal or a call signal of a telephone to a game, a method of transmitting using a dedicated transmission line or A method of transmitting using a signal outside the transmission band of an audio signal is adopted.

When transmitting and receiving a telephone signal using an analog leased line, the line borrowed from the telephone company is 0.3 kHz.
A line that transmits and receives only audio signals in the band from z to 3.4 kHz is used. This is not a problem when one-to-one unselected communication is performed, but normally a communication network that requires selection of one-to-many lines via an exchange is constructed. in this case,
A device for transmitting and receiving signaling and dial signals to the exchange of the partner station, that is, an in-band signal transmission device is required. Sending and receiving signals between telephones using these analog leased lines can be expected to greatly reduce the charge ratio for line use over telephone lines that use ordinary telephone lines, and when constructing a company's communication network, It is a commonly used communication means. When building an intra-company communication network using such an in-band signal transmission device, it is common to build a star-shaped communication network with the head office as the master station and the branch office as the slave station. The in-band signal transmission equipment corresponding to the number of lines is concentrated in, and the slave station side requires the number of lines according to each demand.

[0004]

By the way, a method using a conventional carrier is generally used for an analog signal transmission line. However, when carrying out short-distance communication such as between cities, the carrier is used. The communication line may be stretched between the devices without using it. In such a case, the contact resistance may change at the connection point of the communication line, and this may be a source of noise. For example, when the line loss is suddenly reduced from a state where the line loss is large and a large gain is given in a transmission device such as an in-band signal transmission device, a large volume of noise is generated. In addition to this, pulse-like noise generated inside the exchange and noise generated in each communication line due to other reasons are the same as a normal voice signal from the place where this noise is generated to the communication terminal equipment of the communication destination, a carrier device, It was transmitted through in-band signal transmission equipment and private branch exchanges.

In the conventional in-band signal transmission device, all the signals transmitted to the dedicated line are transmitted in any size with respect to the signals in the band. Therefore, even if unnecessary noise is suddenly superimposed, it will be transmitted to the terminal device of the communication partner as it is, and the recipient will receive a very unpleasant noise at a loud volume that cannot be predicted, avoiding a state that is extremely inconvenient for the recipient. There was a problem that I could not do it.

In particular, when noise is superimposed on the leased line, the frequency or magnitude of the noise is within the range of the signal band or magnitude that can be transmitted by the carrier device, but noise is generated at locations other than the leased line. When it occurs, the frequency or magnitude of noise may be larger than the signal band or magnitude of the carrier, and in this case, it is distorted at the output end of the in-band signal transmitter and transmitted to the exchange side. This may result in noise that is offensive to the recipient. Moreover, this noise has many influences on the human sense organs.

Therefore, an object of the present invention is to provide an in-band signal transmission device capable of suppressing the noise generated on the receiving side line.

The in-band signal transmission device of the present invention comprises an in-band signal transmitting means for transmitting an in-band signal for signaling to the opposite device by using the telephone line, and an in-band signal transmitted from the opposite device by using the telephone line. In-band signal detecting means for detecting an in-band signal for signaling from the received signal, in-band signal removing means for removing the in-band signal from the received signal and transmitting it to the exchange side, and noise detection for detecting noise from the received signal Means and an attenuating means provided after the in-band signal removing means and attenuating the output signal of the in-band signal removing means when the noise detecting means detects noise.

In this in-band signal transmission device, when the noise detecting means detects noise from the received signal from the opposite device, the attenuating means attenuates the output signal of the in-band signal removing means. Therefore, noise is suppressed from the signal transmitted to the exchange side. Further, since the attenuating means is provided after the in-band signal removing means, the in-band signal for signaling is not attenuated and does not affect the transmission of signaling.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 relate to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a communication system to which the in-band signal transmission device of this embodiment is applied.
The system shown in this figure is a configuration example assuming a telephone terminal, and two private branch exchanges 2 and 5 are arranged opposite to each other, and in-band signal transmission devices 3 and 4 are provided on the private line side of each exchange 2 and 5. Is provided and the in-band signal transmission devices 3 and 4 are connected by a dedicated line 7. Each of the exchanges 2 and 5 houses a plurality of telephones 1 and 6, respectively. Here, the telephone set 1, the exchange 2, and the in-band signal transmission device 3 are transmission sides, and the telephone set 6, the exchange 5, and the in-band signal transmission device 4 are reception sides.

FIG. 1 is a block diagram showing the configuration of the in-band signal transmission apparatus of this embodiment. Although only the configuration of the transmission side in-band signal transmission device 3 in FIG. 2 is shown in this figure,
The same applies to the configuration of the reception side in-band signal transmission device 4.

In the in-band signal transmission device 3, as a connection point on the side of the exchange 2, a transmission line connecting end 8 to which a 4-line transmission line (4WS) is connected and a 4-line reception line (4WR) are connected. A receiving line connecting end 12, an SS line connecting end 23 to which a signal transmitting line (hereinafter referred to as SS line) is connected, and a connecting end 19 to which a signal receiving line (hereinafter referred to as SR line) is connected. have. Further, the in-band signal transmission device 3 has a transmission side transmission section transmission point 9 and a transmission side reception section reception point 13 as connection points on the reception side in-band signal transmission apparatus 4 side. The transmission side transmission unit transmission point 9 is connected to the reception side reception unit reception point 11 of the reception side in-band signal transmission device 4 via the transmission side dedicated line 10, and the transmission side reception unit reception point 13 is the reception side dedicated line 14.
It is connected to the reception side transmission section transmission point 15 of the reception side in-band signal transmission device 4 via.

Further, the in-band signal transmission device 3 includes, as the in-band signal transmitting means, a signaling in-band signal oscillator 22 for generating a signaling in-band signal of a single frequency or a plurality of frequencies, and a transmission line connecting end. 8 and the adder 35 that outputs the in-band signal for signaling from the oscillator 22 to the transmission point 9.

Further, the in-band signal transmission device 3 includes a signaling in-band signal detecting detector 20 as in-band signal detecting means. The detector 20 controls the oscillator 22 by the SS signal from the SS line connection end 23 and determines the presence or absence of the signaling in-band signal from the reception signal input from the reception point 13 to determine the signal reception information (hereinafter, S
It is described as R information. ), And is passed from the connection end 19 to the exchange 2.

Further, the in-band signal transmission device 3 has a reception point 1
3, a noise detector 17 for detecting noise from the received signal input from the signal receiving unit 3, a signal-passing in-band signal removing filter 21 provided at a stage subsequent to the noise detector 17, and the filter 2
1 and a noise suppression reception signal attenuator 18 provided in the subsequent stage, and the output signal of the attenuator 18 is output to the receiving line connecting end 12. The noise detector 17 receives the noise suppressing received signal attenuator 18 according to the detected noise level.
To control. The filter 21 is controlled by the in-band signal detection detector 20 for signaling.

Next, the operation of this embodiment will be described.

The voice signal from the exchange 2 is input from the transmission line connecting end 8 to the in-band signal transmission device 3 and added by the adder 35.
Then, the signal is output from the transmitting side transmitting section transmitting point 9 to the transmitting side dedicated line 10. In addition, the signaling in-band signal oscillator 2
The signaling in-band signal generated by 2 is transmitted through the adder 35 at the time of no call and is transmitted from the exchange 2 to the SS.
When the signal is applied, the signaling in-band signal detection detector 20 stops the transmission. Signaling for the exchange and the telephone is performed by the intermittent connection of the signaling in-band signal.

The received signal input from the reception point 13 is input to the signaling in-band signal detection detector 20 and the noise detector 17. FIG. 3A shows an input waveform at the reception point 13. In this figure, reference numeral 30 is a signaling in-band signal, 31 is a voice signal, and 27 is noise. When the signaling in-band signal is cut off during a non-call, the signaling in-band signal detection detector 20 recognizes it as an SR signal and sends it to the exchange 2 as SR information, which is an intermittent DC signal.

The signaling in-band signal detection detector 20 controls the filter 21 based on the SR signal,
The in-band signal for signaling is removed from the input signal so that the in-band signal for signaling is not transmitted to the exchange 2 side through the receiving line.

The noise detector 17 detects the noise by monitoring the magnitude of the received signal, and changes the attenuation amount of the noise suppressing received signal attenuator 18 according to the magnitude of the noise. That is, the noise detector 17 reduces the attenuation amount of the noise suppression reception signal attenuator 18 in a noise-free state, as shown in FIG.
As indicated by reference numeral 27, when a noise that occurs on the receiving side line for an extremely short time, has a large signal magnitude, exceeds the magnitude specified for communication, and has a hearing disorder, is detected, As shown in FIG. 3, period 2 in which noise is generated
The control for increasing the amount of attenuation is made to the noise suppression received signal attenuator 18 so as to correspond to the magnitude of the noise 27 within a time that cannot be perceived by human senses. FIG. 3C shows the amount of attenuation of the noise suppression reception signal attenuator 18, and as indicated by reference numeral 28, the amount of attenuation increases during the period 29 in which noise is occurring.

The signal that has passed through the filter 21 and the attenuator 18, as shown in FIG. 3B, has the signaling in-band signal 30 of the input signal removed and noise 27.
Is suppressed and the voice signal 31 is output to the receiving line.

As described above, according to the present embodiment, even if a large volume of pulse noise is generated, the noise is suppressed to a level that humans cannot perceive. Also,
Since the signaling in-band signal input to the signaling in-band signal detection detector 20 is not attenuated, the communication state is not affected such as the communication being interrupted.

[0024]

As described above, according to the present invention, it is possible to suppress a large volume of noise that cannot be predicted to a low volume within a time period that cannot be perceived by human senses, and obtain good call quality. There is an effect that can be. Moreover, since the attenuating means is provided after the in-band signal removing means, the in-band signal for signaling is not attenuated even if noise is suppressed, and the effect of not affecting the performance of the in-band signal transmission device is obtained. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an in-band signal transmission device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a communication system to which the in-band signal transmission device of one embodiment is applied.

FIG. 3 is a waveform diagram showing a signal waveform in each part of the in-band signal transmission device of FIG.

[Explanation of symbols]

 3 In-band signal transmission device on transmission side 4 In-band signal transmission device on reception side 17 Noise detector 18 Received signal attenuator for noise suppression 20 In-band signal detection detector for signaling 21 In-band signal removal filter for signaling 22 Signaling In-band signal oscillator for

Claims (1)

[Claims] 1. An in-band signal sending means for sending an in-band signal for signaling to an opposite device by using a telephone line, and an in-band signal for a signal received from the opposite device sent by using a telephone line. In-band signal detecting means for detecting a signal, in-band signal removing means for removing the in-band signal from the received signal and transmitting it to the exchange side, noise detecting means for detecting noise from the received signal, and the band An in-band signal transmission device, comprising: an attenuating unit that is provided after the in-band signal removing unit and attenuates an output signal of the in-band signal removing unit when the noise detecting unit detects noise.