JPH0267857A - Code error detecting system for voice channel - Google Patents

Abstract

PURPOSE:To monitor the presence or the absence of code error with a voice channel as the unit by using bits for a dial signal to check the parity of a voice code in a period other than the dial pulse transmission period. CONSTITUTION:When the level change point of a dial transmission (SS) data does not appear over a prescribed time after the level change point, a switching transmission circuit 12 recognizes that a user is not dialing, and the circuit 12 switches parity check data sent from a parity generating circuit 11 and transmits this data instead of SS data after transmitting prescribed-length data indicating the start of parity data insertion. Each channel on the reception side compares the parity check result of a received voice code and parity check data transmitted instead of dial transmission data with each other to detect whether code error of transmission exists or not. Thus, code error is detected with a voice channel as the unit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a code V4 detection method for a voice communication path, and particularly to a voice communication path in a digital multiplex converter that time-division multiplexes and transmits dial signals together with voice signals. This invention relates to a code error detection method.

[Conventional technology]

Conventionally, this type of multiplex conversion device adds frame bits, etc. to a digital signal obtained by pulse code modulation of an audio signal and a signal obtained by simple sampling of dial pulses, and converts them into frames in a predetermined format. are configured and time-division multiplexed.

Detection of code errors in the transmission of multiplexed signals is performed at a stage after frame configuration, such as bipolar code violation and CR detection.
This is done by detecting C-test failures, etc., but in either case, it is impossible to detect code errors on a per-voice channel basis, that is, to detect in which channel a code error occurs. [Problems to be solved] With the conventional audio multiplexing converter described above, it is impossible to detect code errors for each voice communication path, so especially when data modem transmission is performed frequently on the voice communication path and the effects of code errors are likely to become obvious, The disadvantage is that in order to detect code errors (code errors on each communication path), it is often necessary to perform tests using code error testing equipment while the use of that communication path is discontinued.
[Means for Solving the Problems] The voice channel code error detection method of the present invention combines a plurality of voice codes obtained by pulse code modulating an audio signal and dial transmission data obtained by sampling a dial signal. In this method, transmission is performed by time division multiplexing between communication paths, and in each communication path on the sending side, when a dial pulse appears in the dial transmission data, it is transmitted as is, and during the period when the dial pulse does not appear, the voice code is transmitted. parity check data is transmitted in place of the dial transmission data, and each of the communication paths on the receiving side receives the parity check result of the received voice code and the parity check data sent in place of the dial transmission data. The presence or absence of the code mb being transmitted is detected by comparison.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. FIG. 2 is a signal waveform diagram for explaining the operation of this embodiment. A communication path transmitting unit 1 on the transmitting side receives a voice code obtained by pulse code modulating a voice signal and SS data obtained by sampling a dial transmission (SS) signal, and sends the voice code to a multiplexing circuit 2. At the same time, the parity generation circuit 11 counts the number of digital values 111 in the voice code and outputs the parity data and SS data to the switching transmission circuit 12.
and sends it to the multiplexing circuit 2. The multiplexing circuit 2 converts the voice codes sent from the plurality of channel transmitting units 1 into predetermined seven
At the same time, the output data of the switching transmission circuit 12 is inserted into the dial signal bit and transmitted to the other station. On the receiving side of the partner station that receives this, a separation circuit 3 separates the voice code and dial signal bit of each communication path and distributes it to each communication path receiving section 4. In the communication path receiving section 4, the switching receiving circuit 42 receiving the dial signal bit switches between the parity bit and the 88 data.
The former is sent to the comparison circuit 43, and the latter is sent as SR data.
The respective sending/comparing circuits 43 compare the parity data obtained by the parity generation circuit 41 by counting the number of 111s in the voice code and the parity data given from the switching reception circuit 42, and detect a mismatch between the two. In particular, an error signal indicating the presence or absence of a code error is generated and sent out. The 88 data sent to the switching transmission circuit 12 is binary data obtained by sampling the SS signal shown in FIG. In other words, the SS signal is at an open level when there is no call, and during dialing it is set at a maximum of 20 pulses/second.
A dial pulse of 4 (occupancy rate) of 33% appears and becomes earth level during a call. If the level change point of the SS signal does not appear for a predetermined period of time after the level change point of the SS signal, the switching transmission circuit 12 considers that dialing is not in progress, and after transmitting data U1 of a predetermined length indicating the start of parity data insertion. , the parity data (
P) and sends it to the multiplexing circuit 2. After this, when a level change point of the SS signal appears while transmitting parity data (P), the switching transmitter circuit 12 immediately stops transmitting parity data and transmits data U2 of a predetermined length indicating the stop of parity data insertion. After that, the switching receiving circuit 42 on the receiving side holds the level of the SR signal when receiving the data U1 and transmits the parity data (P) to the comparing circuit 42. When data U2 is received, the holding of the level of the SR signal is released, and the signal transmission to the comparator circuit 42 is stopped.

Normally, the time during dialing is extremely short compared to the time during no calls and during calls, so the time required for dialing signals is very short.

The rate at which bits are used as parity check bits becomes very high.

〔Effect of the invention〕

As explained above, in the present invention, the presence or absence of code errors can be monitored on a per voice channel basis by using G for dial signals and for parity checking of voice codes during a period other than when dial pulses are sent. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a signal waveform diagram for explaining the operation of the embodiment of the present invention. l...Call path transmitter, 11...Parity generation circuit, 12...Switching transmitter circuit, 2...
...Multiplexing circuit, 3... Separation circuit, 4...
. . . Communication path reception section, 41 . . . Parity generation circuit, 42 . . . Switching reception circuit, 43 . . .
Comparison circuit. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] This is a method in which the voice code obtained by pulse code modulating the voice signal and the dial transmission data obtained by sampling the dial signal are time-division multiplexed and transmitted between multiple communication paths. When a dial pulse appears in the dial transmission data, it is transmitted as is, and during a period when the dial pulse does not appear, parity check data of the voice code is transmitted instead of the dial transmission data, and in each of the communication paths on the receiving side. A code for a voice channel, characterized in that the parity check result of the received voice code is compared with the parity check data sent instead of the dial transmission data to detect the presence or absence of a code error during transmission. Error detection method.