JPS5820517B2 - Sampling control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an audio signal sampling control method in a PCM communication system when an audio information communication system is used.

In a PCM communication system, it is necessary to sample an analog voice signal and encode it using a pulse amplitude modulation (PAM) L encoder.

When sampling analog audio signals, it is conventional to simultaneously multiplex them onto a high-speed (for example, 1.544 Mb/s) line.

In other words, sampling pulses are fixedly sent in sequence at a fixed period to sampling gates provided on each of a plurality of lines, and each line is time-division multiplexed into a high-speed line at the position of the sampling pulse.

Figure 1 shows an example of the conventional method, in which the transmission line is PCM.
This is an example of

SUB 1 to n are subscribers, SCM is a scanning device, SW is a communication path switch T is a trunk, LPF is a low-pass filter, S
G is a sampling gate, SP is a sampling pulse supply circuit, MPXJ is a multiplexer, and C0DBC is a code and a decoder.

Now, when the subscriber 5UB1 makes a call, the call is detected in the scanning circuit SCN that constantly monitors the status of the subscriber through the subscriber line circuit, and this information is sent to the central control unit (not shown). Under the control of this central control unit, an empty trunk T is acquired, the communication path switch SW is closed, and a communication path is established.

When a call is started, the audio signal of 5UB1 passes through the set communication path and LPF and is sampled at the sampling gate SG.

Sampling pulses are fixedly supplied to all SGs from the sampling pulse supply circuit, channel positions are set in the order in which the sampling pulses are supplied, and multiplexing is performed in the multiplexer MPX. Furthermore, it is encoded by an encoder/decoder CODEC and sent to a transmission line.

In this way, conventional analog signal sampling involves supplying temporally fixed sampling pulses to all SGs to perform sampling and multiplexing at the same time. The relationship between the location and each analog line was fixed.

Therefore, when such a sampling method is applied to a low-efficiency line such as a subscriber line to perform line concentration, a line concentrator for concentrating the analog line or the multiplexed link is required in addition to the sampling and multiplexing apparatus.

The present invention solves this drawback and will be described in detail below with reference to the drawings.

FIG. 2 is a diagram showing one embodiment of the present invention, where CNT is a sampling control section, SCM is a sampling control memory, and D
EC is a decoder, SW is a switching center, M is a multiplex link, and the others are the same as in FIG. 1.

Now, when a certain subscriber makes a call, the sampling control unit CNT, upon receiving the call information from the scanning device SCN, notifies the central control unit (not shown) of the exchange to that effect.

The central controller searches for an empty time slot on the multiplexed link and writes the line number to be sampled at that time (calling line number) in the position corresponding to that time slot number on the SCM.

The SCM sequentially outputs the line numbers that have been written.
A line number successively output in a certain time slot time is decoded by a decoder DEC, and a sampling pulse is supplied to the sampling gate of the line indicated by its output in that time slot time.

The sampled information is multiplexed with MPX and C0DE
Encoded in C.

FIG. 3 is a diagram showing the sampling control memo IJscM.
Tn is a time slot number, Ln is a line number, DEC is a decoder, SG is a sampling gate, and CNT is a sampling control unit.

When a subscriber makes a call, the central controller notifies the CNT of the empty time slot number Tn in association with the line number from which the call was made, as described above.

The CNT writes the calling line number in the time slot number corresponding section of the SCM.

Similarly, for the line on the receiving side, the S
The incoming line number is registered on the CM.

In SCM, the line numbers written in the time slot number corresponding section are successively extracted in accordance with each time slot time on the multiplexed link, and a sampling pulse is sent to the line indicated by the successively extracted line numbers. Let it be supplied.

As explained above, according to the present invention, only the information of the line on which the call was made or received is sampled and multiplexed on the multiplex link, so that it is possible to add a line concentration function to the antacid.

In other words, it is now possible to perform sampling and concentrating multiplexing at the same time, and compared to conventional methods in which sampling and multiplexing are performed after concentrating analog lines, or sampling and multiplexing are required. It is possible to share and economically construct a time-division communication system.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a system to which a conventional sampling sterilization method is applied, and FIG. 2 is a diagram showing an example of a system to which an embodiment of the present invention is applied. Further, FIG. 3 shows a basic configuration diagram of the sampling control memory in the present invention. SG represents a sampling gate, SCM represents a sampling control memory, and CNT represents a sampling control unit.

Claims (1)

[Claims] 1. In a communication conversion system that samples analog voice signals from a line and converts them into digital signals, a sampling pulse supply circuit that supplies sampling pulses to a sampling gate that performs sampling is connected to the line to be sampled at each time position. 1. A sampling control method characterized by comprising a memory which is rewritable according to the state of use of a line and controls the supply of sampling pulses.