JPH04200095A - High quality voice talking system - Google Patents

Abstract

PURPOSE:To enhance the transmission quality of a voice signal by sending an analog signal through the same transmission capacity as that of two channels used by a digital subscriber circuit. CONSTITUTION:A voice band of a 13-bit CODEC (CODEC) C1 of an analog subscriber circuit is selected to be 3.4kHz, which is the same as that of a conventional 8-bit CODEC, and a dynamic range in the band is enhanced by using 16-bits per sample with respect to 8kHz sampling. Moreover, the 16-bit CODEC C1 requires a transmission capacity of 16-bit X 8kHz and divided into two of 8-bit X 8kHz per one channel and outputted to a data highway (DHW). That is, the 16-bit CODEC C1 uses a 8kHz clock signal to sample a voice band signal and uses a highway clock signal to use two channels of an 8-bit X 8kHz band. Thus, the quality of the analog subscriber circuit is improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a high-quality voice communication method for a system in which digital subscriber circuits and analog subscriber circuits coexist, the use efficiency of the data highway is improved, and the quality of the analog subscriber circuits is improved. A switching system in which ISDN digital subscriber circuits and analog subscriber circuits are used in combination, using two channels with a transmission capacity of 64 Kbps, with the aim of providing a high-quality voice communication system with improved performance. wherein the analog subscriber circuit is sampled at least one of 16 bits per sample with an 8KHz sampling clock or 8 bits per sample with a 16KIIz sampling clock for use by the digital subscriber circuit (DLC). Configure it for analog communication with the transmission capacity for the channel.

(Industrial Application Field) The present invention relates to a switching system, and more particularly to a high-quality voice communication system for a system in which digital subscriber circuits and analog subscriber circuits coexist.

[Conventional technology]

As ISDN is put into practical use and developed, there is a need for a switching system that mixes and uses digital analog subscriber circuits (ALCs) for ISDN.

In such a system, as shown in FIG.
and an analog subscriber circuit (ALC) are inserted into the back wiring board (BWB). Each circuit uses two channels within the data highway connected to the back wiring board (BWB). The selection of this circuit corresponds to the requirements of users and the like, and it is determined whether it is used in a digital subscriber circuit or an analog subscriber circuit. Note that both the digital subscriber circuit and the analog subscriber circuit have the same interface for the data highway, and are configured so that either can be used.

[Problems to be Solved by the Invention] When the ISDN digital subscriber circuit and the conventional analog subscriber circuit ALC are used together as described above, the number of channels used in the analog subscriber circuit is 64.
This is one channel of Kbps transmission capacity, and only one of the two channels provided for the digital subscriber circuit is used. In other words, conventionally, when used as an analog subscriber circuit,
There were unused slots in the data highway slots, etc., and when used as a whole system, the usage efficiency was poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-quality voice communication system that improves the efficiency of data highway usage and improves the quality of analog subscriber circuits.

[Means for solving the problems and their effects] The present invention has 64
This is a switching system used as an ISDN digital monitor that uses two channels having a transmission capacity of Kbps.

Analog subscriber circuits are sampled at least one of 16 bits per sample with a sampling clock of 8 KHz or 8 bits per sample with a sampling clock of 16 KHz, and the transmission capacity for two channels used by the digital subscriber circuits is Transmit analog signals with the same transmission capacity.

This transmission is for two channels with a transmission capacity of 64 Kbps, and the quality of the analog line is improved compared to the conventional analog capacity.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

There are two methods for improving the quality of voice calls over analog lines. One method is to increase the number of bits per sample without changing the communication band; for example, the sampling frequency is 8KIIz and the number of bits per sample is 16 pinto. On the other hand, the communication band is expanded without changing the number of bits per sample; for example, 8 bits per sample and a sample frequency of 16
Ktiz.

In a conventional analog line, the number of bits per sample was 8 bits at a sampling frequency of 8Ktlz. On the other hand, in the first method of the present invention,
A codec that converts audio signals and digital data (
8K using 16-bit cODEc (CO'DEC)
l(operate at a sampling frequency of z.

FIG. 1 is a block diagram of a first embodiment of the present invention.

The voice band of the analog subscriber circuit 16-pin C0DECC1 is 3.4 KHz, which is equivalent to the conventional 8-pin CODEC, but the 8K) Iz sampling uses 16 bits per sample to increase the dynamic bandwidth within the band.・Raise the range. Also, this 16-bit CODEC is 1
Although it requires a transmission capacity of 6 bits x 8 KHz, each channel is divided into 8 bits x 8 KHz digital data and output to the data highway (DHW). That is, for the 16-bit CODECC1, the audio band signal is sampled using the 8K)Iz clock signal, and two channels of the aforementioned 8-bit x 8Kllz band are used using the highway clock signal. In the first method described above, by increasing the number of bits, the reproducibility of the waveform of the audio signal is increased and the dynamic range is improved.

FIG. 2 is a block diagram of a second embodiment of the present invention.

In the second embodiment, the second method described above is used, and the audio band signal is set to 6.8KJ (up to z, and 16KJ).
Audio data is converted by Hz sampling. That is, in the second method, 8-bit C0D
ECC2 is used, a 16Kllz sampling clock signal is added, and 8-bit conversion data is obtained by 16KHz sampling. This 8 pino l-cod
The output of EC is 8-bit, 16K) data and is added to buffer register B1. Buffer register B1
The total capacity for 2 channels is 16 bits)/8Ktlz. The buffer register B1 has a clock signal of 8Ktlz and the highway clock signal has a clock signal of 16KIIz.
A clock signal of 16K11z is added, and this clock signal of 16
5Kl-1z audio data is accessed and 16 bits/
Convert 8KIlz audio data. Then, audio data of 16 bits/8K) Iz is output to the data highway (BHW) in accordance with the highway clock signal. Also, the signal applied from the data highway is converted into an audio signal in the 6.8 K11z band by the reverse route.

As mentioned above, in the first embodiment, the bit width processed by C○DEC is increased, whereas in the second embodiment, the communication band is improved to 6.8 KI4z.

FIG. 3 is an explanatory diagram of time slots of the data highway. There are two B channels (Bl, B2) used by the digital subscriber circuit DLC, and two time slots are allocated consecutively. Further, in the conventional analog power input circuit, the used band is one channel (SO), so an unused portion W exists at the rear front of the audio data. However, in the case of the analog subscriber circuit ALC according to the invention, the same capacity as the digital subscriber circuit DLC is required for the voice data Sl, S2.
Since the time slots are used as the same, there are no unused slots, and the efficiency of time slot usage is not reduced. Furthermore, since the transmission capacity of digital data obtained by converting the audio signal is doubled, the dynamic range and band of the audio signal are expanded.

FIG. 4(A) is a system configuration diagram of an embodiment of the present invention.
Figure (B) is a timing chart corresponding to channels. The input of the exchange switch 5WITCH is the multiplexer MPX.
is provided. This multiplexer MPX allows digital subscriber circuit DLC, analog subscriber circuit AL
Each data highway front for C is assigned. For example, a total of 128 digital subscriber circuits DLC and analog subscriber circuits ALC are connected to one MPX. The multiplexer MPX selects data on 128 lines (each line has a capacity of (2B)) and multiplexes the data for transmission.

With the above configuration, the present invention improves the quality of analog signal transmission, but the present invention is not limited to this. For example, even if the other party is a system to which a conventional ALC is connected, by setting the unused portion of data to O, it is possible to communicate with the same quality as the conventional one.

〔Effect of the invention〕

As described above, according to the present invention, the transmission quality of audio signals can be improved by effectively using the unused time slots 1 to 1.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the first embodiment of the present invention, Fig. 2 is a block diagram of the second embodiment of the present invention, Fig. 3 is an explanatory diagram of time slots, and Fig. 4 (A) is a block diagram of the second embodiment of the present invention. System configuration diagram of an embodiment of the invention, No. 4
Figure (B) is a timing diagram, and Figure 5 is an explanatory diagram of a mixed system of DLC and ALC.

Claims (1)

[Claims] ISDN digital subscriber circuit (DLC) using two channels with a transmission capacity of 64 Kbps.
) and analog subscriber circuits (ALCs), the analog subscriber circuits are sampled at 16 bits per sample with an 8 KHz sampling clock, or 16 bits per sample with a 16 KHz sampling clock. A high-quality voice communication system characterized in that analog communication is carried out using at least one of 8 bits and has a transmission capacity equivalent to the channel used by the digital subscriber circuit (DLC).