JPH0193227A - Signaling inserting circuit - Google Patents

Abstract

PURPOSE:To improve deterioration in the quality of a voice signal by substituting a digital signal of prescribed bits in inputted digital signals of N bits for signaling information which detects the change point of a dial pulse, and sending a PCM signal of prescribed bits for the information other than that. CONSTITUTION:The dial pulse and a sampling pulse are added on the D terminal and the CK terminal of a D-FF11, and the exclusive OR of the output and the one in which the output is shifted by one bit via a D-FF21 is taken at an EX-OR gate 22, and the 8th bit of the voice signal is replaced by the signaling information from the D-FF11, then, it is sent via an FF of 8 bits. Also, while no output from the EX-OR gate is issued, the 8th bit of a voice PCM signal is sent out via an FF13. In such a way, since it is possible to perform the transmission of the signaling information at speed 1/100 the on-going speed, the part of the voice PCM signal of 8 bits is increased, thereby, the deterioration in the quality of the voice signal can be improved.

Description

[Detailed Description of the Invention] [Summary] For example, with respect to a signaling insertion circuit used in an audio signal processing device, the present invention aims to improve the quality deterioration of an audio signal caused by inserting signaling multi-information into an audio PCM signal. Signaling that includes a change point detection means for detecting a change point of input signaling information, and a change point detection means that uses the output of the change point detection means to replace a predetermined bit digital signal of an input N-bit digital signal with the signaling information. and information replacement means.

[Industrial application field]

The present invention relates to a signaling insertion circuit used, for example, in an audio signal processing device.

In the process of converting an audio signal into a PCM signal, the audio signal processing device inserts telephone signaling information (dial pulses) etc. into the above PCM signal and transmits it. It is necessary to insert signaling information so as to reduce the number of signals.

[Conventional technology]

FIG. 4 is a frame configuration diagram of a PCM signal, FIG. 5 is a block diagram of a conventional example, and FIG. 6 is an explanatory diagram of the operation of FIG.

First, in recent years, LSIs with various functions have been developed and put into practical use, and among them is a single channel encoder LSI.

This single channel encoder (hereinafter abbreviated as encoder 7, not shown) performs sampling on the transmitting side.

Quantization, encoding, decoding, and interpolation filtering on the receiving side are realized on a single LSI chip.When an audio signal is input on the transmitting side, it is converted into an 8-bit audio PCM signal as shown in the word structure in Figure 4. is output, but the timing of transmission is staggered to facilitate multiplexing.

Therefore, this audio PCM signal is divided into 8 bits at a time, for example, 2 bits each.
After four channels are multiplexed together, one bit (called F bit) is added to the beginning of this multiplexed pulse and sent out, and the transmission rate at this time is 1.544 Mb/s.
becomes. The minimum unit during this multiplexing is a frame (
(Refer to the frame structure in FIG. 4), when this frame is repeated 9, for example, 24 times, the usage of the added F bit completes, and this is called a multi-frame.

For example, in the 6.12.18.24 frame (referred to as the signal frame), the 8th bit of each channel is replaced with the signaling information bit S, so in this signal frame, the audio signal is 7 bits. Become.

Next, the 8-bit audio PCM signal from the encoder described above is applied to the input terminal IN on the left side of FIG. The dial pulse shown in Figure 6-〇 is the D-FF
For example, I KH shown in Figure 6-■ to the CK terminal of 11
A sampling pulse of order z (only the rising point is shown) is applied respectively.

Therefore, from the Q terminal of D-FF 11, 1, for example 00...
The signaling information of 111... is output, but since the selector 12 has selected the 9-dotted line side at this time, the audio PCM
Instead of the 8th bit pulse (least significant bit) of the signal,
This signaling information is added to FF13, and FF1
A PCM signal consisting of a 3- to 7-bit audio PCM signal and 1-bit signaling information is transmitted.

[Problem that the invention seeks to solve]

Here, as described above, sample the dial pulse with a sampling clock of about l[lz.

It is replaced with the 8th bit of the audio PCM signal, but at this time,
There is a problem in that the quality of the audio signal deteriorates every time the audio signal is encoded with 7 bits.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, 2 is a change point detecting means for detecting a change point of input signaling information, and 1 is a change point detecting means for detecting a change point of input signaling information, and 1 is a change point detecting means for detecting a predetermined bit of a digital signal of an input N-bit digital signal using the output of the change point detecting means. This is a signaling information replacement means that replaces the signaling information with the signaling information.

[Effect]

In the present invention, the waveform of the dial pulse has few changing points, and the logic is fixed at an H level state or an L level state for a long time.

Therefore, the changing point detection means 2 replaces the digital signal of the dial pulse with a digital signal of a predetermined bit, but otherwise sends a PCM signal of a predetermined bit. This improves the quality deterioration of the audio signal.

〔Example〕

FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 shows the components shown in FIG. Note that the symbols on the left side of FIG. 3 indicate the waveforms of the portions with the same symbols in FIG. Also, the same reference numerals indicate the same objects throughout the figures.

The operation shown in FIG. 2 will be explained below with reference to FIG.

) is applied to the D terminal and CK terminal of the D-FF 11, so the state 1 of the dial pulse at the rising point of the sampling pulse, for example 0011, is output from the Q terminal.

Then, the exclusive OR (hereinafter abbreviated as EX-OR) of the output of this D-FF 11 and this output further shifted by 1 bit through the D-FF 21 is calculated as EX-O.
When taken by the R gate 22, an output of 1 is obtained at the change point of the dial pulse. Therefore, this output drives the selector 12 to replace the 8th bit node of the audio PCM signal with the signaling information from the D-FFII and send it out via the 8 bit node FF. Note that while the output from the EX-OR gate is not sent out, the 8th bit of the audio PCM signal is sent out via the FF 13.

In other words, it is possible to transmit signaling information at about 1/100th the transmission speed of the conventional one, so 8-bit voice PC
The M signal portion is increased, and the quality deterioration of the audio signal is improved.

〔Effect of the invention〕

As described above in detail, according to the present invention, deterioration in quality of audio signals is improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is an explanatory diagram of the operation of Fig. 2, Fig. 4 is a frame configuration diagram, and Fig. 5 is a conventional example. A block diagram of FIG. 6 is an explanatory diagram of the operation of FIG. Change rcA'l Ikomushi Me7 Figure I) Heavy η production ShiL Sun Moon To 4th 3rd generation 7th story - 滄き岱ノ - F/kbps Flow Nokui Shiba Table Example 7th Rock 5th Figure 5 movement γ evening tomorrow

Claims (1)

[Claims] Change point detection means (2) for detecting change points of input signaling information; and N bits (N is a positive integer) to be input using the output of the change point detection means (2). 1. A signaling insertion circuit comprising: signaling information replacement means (1) for replacing a predetermined bit of a digital signal of a digital signal with the signaling information.