JPS61131929A - Signal information transmission system in digital carrier communication equipment - Google Patents

Abstract

PURPOSE:To transmit signal information without lowering a voice signal by intermitting a tone signal of a frequency band not overlapped with a voice signal frequency by means of the signal information to be transmitted and applying PCM coding the intermittent signal, synthesizing it with a PCM code of the voice signal and transmitting/receiving it. CONSTITUTION:A signal generated by an oscillator 7 is subjected to frequency division 8, converted into a tone signal in 3.825kHz of an idle frequency band of the voice signal and intermitted by a switching circuit 9 depending on the binary value of signal information SS to be transmitted. The intermitted tone signal is converted into a PCM code of linear characteristic by a coder 10, the PCM of the signal information is added to the PCM code of the voice signal by an adder 11 and transmitted to a repeater after being converted into an ADPCM code by a coder 4. On the other hand, when the ADPCM signal is received, it is converted into the PCM code by a decoder 5 and transmitted to a digital filter 12. Then the signal is decomposed into the signal component of 3.4-4.0kHz and the voice signal of 0.3-3.4kHz, the signal component is subjected to level identification 13 and the voice signal component is converted into the PCM code with companding by a compressor 6 and then demodulated into the voice signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a signal information transmission system in a digital carrier communication device that transmits voice signals and signal information for telephone calls after being PCM encoded.

[Technical background of the invention]

2. Description of the Related Art Conventionally, a digital carrier communication device (PCM terminal station) that encodes and transmits a voice signal for a call using PCM code transmits signal information together with the voice signal.

FIG. 2 is a block diagram showing a schematic configuration of an ADPCM method among conventionally used digital carrier communication devices. (It is input to the PCM encoding/decoding unit 2 via the Z bandpass filter 1, and is converted into a companded 64 bits/second PCM code. After that, the encoder 4 converts the code into an adaptive predictive code (ADPCM code) and sends it to the repeater.

On the other hand, the received ADPCM code is decoded by a decoder 5, converted into a companded PCM code by a compressor 6, and further converted into an audio signal with linear characteristics by an encoder/decoder 2. demodulated. Then, the demodulated audio signal is outputted as a received audio signal after unnecessary components such as high frequency components are removed by a bandpass filter 1.

Conventionally, the signal information to be transmitted together with the audio signal is transmitted by assigning a specific transmission channel for the PCM-encoded audio signal, or by transmitting a specific bit only once per multiple frames of the PCM-encoded audio signal. It is transmitted using one of the methods of allocating and transmitting. Specifically, in the former method, the transmission speed is 2.048
The latter method is used in 24-channel PCM terminal stations with a transmission rate of 1.544 Mbit/sec.

[Problems with background technology]

However, the method of allocating signal information to a specific transmission channel for transmission reduces the economic efficiency of the transmission path, and the method of allocating and transmitting specific bits causes part of the audio signal to be lost, resulting in a loss of audio quality. There was a problem that transmission quality deteriorated.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned conventional problems, and is to improve signal information in a digital carrier communication device that allows signal information to be transmitted without deteriorating the economic efficiency and transmission quality of the transmission path. The purpose is to provide a transmission method.

[Summary of the invention]

This invention has an audio signal transmission band of 0.3 to 3.4KH.
Focusing on the fact that O~Q, 3KH2, and 3.4~4KH2 are blank bands in telephone lines, etc., the tone signals in these blank bands are intermittent depending on the signal information to be transmitted. The above objective is achieved by further performing PCM encoding, adding the signal to the PCM encoded audio signal, and transmitting the signal.

(Embodiment of the invention) Figure 1 shows a digital carrier communication device (P
2 is a block diagram illustrating an embodiment of a main part of a CM terminal station;
The oscillator 7 generates a tone signal having a single frequency component of, for example, 8 KHz.

This 3KH2 tone signal is multiplied by 11/23 in the divider 8, and is 3.825KH2 within the blank frequency band of the audio signal.
is converted into a tone signal. This tone signal of 3.825KH2 is input to the switching circuit 9 and is interrupted in accordance with the binary value of the signal information SS to be transmitted. As a result, the signal information SS is converted into an intermittent tone signal of 3.825 KHz.

This intermittent signal is input to an encoder 10, converted to a PCM code with linear characteristics, and inputted to an adder 11.
M code is input.

Therefore, in the adder 11, an operation is performed in which the PCM code of the signal information is added to the PCM code of the audio signal.
It is output as a PCM code containing signal information components. Then, the PCM code outputted from the adder 11 is converted into an ADPCM code in the encoder 4 as in the conventional case and sent to the repeater.

On the other hand, when an ADPCM code containing a signal information component is received, this ADPCM code is converted into a PCM code by the decoder 5 and input to the digital filter 12 . and,
In this filter 12, 3.4 to 4.0 KH2 (D
The signal component and the audio signal of 0.3 to 3.4 KH2 are separated, and the level of the signal component of 3.4 to 4.9 KH2 is identified by a level discriminator 13. That is, the level discriminator 13 adds 3.8 to the signal component extracted by the filter 12.
Whether there is a 25KHz component or not is identified by its level, and if there is a 3.825KH2 component, logic "1"
If there is no signal, a logic "O" signal is output, and this is output as the demodulated signal SR of the signal information SS.

On the other hand, 0,3~3.4KH2 separated by filter 12
The component is the PC compressed by the compressor 6 as before.
After being converted into M code, the encoder/decoder 2 demodulates it into an audio signal.

Therefore, according to this embodiment, there is no need to insert signal information into the transmission channel or transmission bit of the audio signal for transmission, thereby preventing deterioration of the economic efficiency of the transmission path and the audio quality.

Note that the tone signal for transmitting signal information is 9.3K.
A frequency band below H2 may be used. Further, the oscillation signal for creating this tone signal may use the audio signal sampling clock (8KH2).

〔Effect of the invention〕

As is clear from the above description, in the present invention, a tone signal in a frequency band that does not overlap with the audio signal frequency is intermittent depending on the signal information to be transmitted, and the intermittent signal is converted into PCM.
Since the signal information is transmitted by encoding and combining it with the pcM code of the audio signal, the signal information can be transmitted without reducing the economic efficiency of the transmission path or the audio quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of essential parts showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a conventional digital carrier communication device. DESCRIPTION OF SYMBOLS 1...Bandpass filter, 2...Encoder/decoder, 3...Extender, 4...Encoder, 5...Decoder,
6... Compressor, 7... Oscillator, 8... Frequency divider, 9
...Switching circuit, 10...Encoder, 11...
-Adder, 12...Digital filter, 13...Level discriminator.

Claims (1)

[Claims] A digital carrier communication device for PCM-encoding voice signals and signal information and transmitting the encoded signals via a line, comprising an oscillation means for oscillating a tone signal consisting of a single frequency component outside the frequency band of the voice signal, and an output from the oscillation means. and a switching means for intermittent tone signals according to the signal information to be transmitted, and the signal information is transmitted by PCM-encoding the output signal of the switching means and adding it to the PCM-encoded signal of the audio signal, A signal information transmission system in a digital carrier communication device, characterized in that on a receiving side, the single frequency component is extracted from a demodulated signal of a received PCM encoded signal by digital processing, and signal information is demodulated by the output thereof.