JP2522440B2 - Audio signal PCM multiplexing system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a PCM multiplexing system of a voice signal in a PCM-30 channel multiplex converter for converting a switch signal and a voice signal into PCM to multiplex 30 channels. Is.

[Prior Art] FIG. 2 shows a block diagram of a device to which a conventional PCM multiplexing system for audio signals is applied. In the figure, 26 to 28 are speech path boards, 29 to 31 are analog audio signal lines, 32 to 34 are A / D converters, 35 to 37 are output buffers, 38 is a common control board, 39 is an audio signal multiplexing circuit, 40 is a multi-frame generation circuit, 41
Is a 2 MHz _Z PCM line.

According to the conventional audio signal PCM multiplexing method, the analog audio signals input via the analog audio signal lines 29 to 31 are converted into audio signals encoded by the A / D converters 32 to 34 at different timings. To be converted. Then, the encoded audio signals are output to the respective output buffers 35.
Is transmitted to the common control board 38 via the buses individually provided to the communication path boards 26 to 28, and is then multiplexed by the voice signal multiplexing circuit 39 in the common control board 38. Thus
Audio signals multiplexed by an audio multiplexing circuit 39 is generated as a multi-frame by the multi-frame generating circuit 40 is sent on line 41 of 2 MH _Z.

[Problems to be Solved by the Invention] In the above-mentioned conventional PCM multiplexing system for audio signals, the common control panel is provided for each encoded audio signal output from each speech path panel via a bus provided individually. Since the audio signal is multiplexed by the voice signal multiplexing circuit provided in this, it is necessary to have the same number of bus wirings as the number of mounted communication channels, and in the common control panel for multiplexing. Since the audio signal multiplexing circuit is provided, there is a problem that the number of wirings and the number of parts are increased, the circuit configuration becomes complicated, the cost is increased, and the reliability is lowered.

[Means for Solving the Problem] In order to solve such a problem, a PCM multiplexing system for audio signals according to the present invention provides an analog audio signal in an apparatus equipped with a common control board and a plurality of speech path boards. A / D converter that encodes and outputs as a PCM audio signal, GND detection circuit that detects the ground level signal given from the common control panel by inserting the speech path board, and A / D converter after the speech path board is inserted Based on the timer that generates the output to block the PCM audio signal that is sent until the normal operation starts, and this timer output
A gate circuit that blocks the output signal of the A / D converter, and a field effect transistor that multiplexes and outputs the PCM audio signal from the gate circuit by the output terminal being wired or connected to the other output terminals of the speech path board. It is equipped with.

[Operation] When the speech path board is inserted, the output of the PCM audio signal of the A / D converter is blocked by the gate circuit for a certain period of time, and then the PCM audio signal that has passed through the gate circuit is an electric field whose output terminals are wired or connected. The signals are multiplexed and transmitted by the effect transistors.

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

FIG. 1 is a block diagram showing an embodiment of an apparatus to which the PCM multiplexing system for audio signals according to the present invention is applied. In the same figure, 1 to 3 are communication road boards, 4 to 6 are GND detection circuits, and 7
-9 is a timer for blocking the output of the voice signal for a certain period of time when the call route boards 1 to 3 are inserted, 10-12 are analog voice signal lines, and 13-15 code the analog voice signals at different timings. A / convert to a converted audio signal
D converter, 16 to 18 gates, 19 to 21 field effect transistor, 22 a common control board, 23 ground, 24 multi-frame generating circuit, 25 is a PCM line of 2 MH _Z.

Next, the operation of the above embodiment will be described. This call base 1
Each of the blocks in 3 to 3 has the same configuration, and therefore, when the communication path boards 1 to 3 are inserted into the corresponding slots, the operations are the same. Here, only the operation when the communication path board 1 is inserted into a predetermined slot will be described.

When the communication path board 1 is inserted into the specified slot, the ground level signal from the ground 23 of the common control board 22 becomes GND.
It is given to the detection circuit 4. And this GND detection circuit 4
Detects the ground level signal and starts the timer 7.

The output of the timer 7 outputs a signal of "L" level for a certain time while the timer 7 is activated, and this output signal is sent to one input terminal of the gate (logical product circuit) 16.

On the other hand, the analog audio signal from the analog audio signal line 10 is encoded by the A / D converter 13 and sent to the other input terminal of the gate 16. Since the "L" level output signal of the timer 7 is sent to one input terminal of the gate 16 for a certain period of time until the A / D converter 13 operates normally, the gate 16 is turned off. No matter what audio signal is sent to the other input terminal of the cage gate 16, the output of this audio signal is blocked for a certain period of time.

Then, after the elapse of a certain time, the output signal of the timer 7 becomes "H" level and is sent to one input terminal of the gate 16, so that the gate 16 is turned on and sent to the other terminal. The encoded audio signal can pass through the gate 16. Then, the encoded voice signal is sent to the common control board 22 by the field effect transistor 19, and the output of the field effect transistor 19 is the field effect transistor in another speech path board. Since it is connected to each of the outputs by wired OR, the coded voice signal is multiplexed here with the coded voice signal that is sent out from other speech path boards at different timings, and the common control board Sent to 22.

As described above, the present invention is provided with the timer for blocking the output of the encoded audio signal for a certain period of time until the A / D converter performs the normal operation, so that the other communication route boards are encoded. While preventing the risk of erroneous data being superimposed on this normal audio signal data during audio signal transmission, and enabling the audio signal to be multiplexed by wired OR, the wiring and the number of parts are reduced. This has the effect of simplifying the circuit.

[Effects of the Invention] As is clear from the above description, according to the audio signal PCM multiplexing system of the present invention, when the speech path board is inserted, the PCM audio signal output of the A / D converter is output by the gate circuit. Was blocked for a certain period of time and then passed through the gate circuit
Since the PCM voice signal is multiplexed by the field-effect transistors connected in a wired or connection, it is not necessary to provide a voice signal multiplexing circuit for performing the multiplexing,
Further, there is an effect that the number of bus wirings can be reduced, the number of components and the number of wirings can be reduced, and a simple circuit configuration can be achieved, and an economical and highly reliable device can be configured.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus to which a voice signal PCM multiplexing method according to the present invention is applied, and FIG. 2 is an embodiment of an apparatus to which a conventional voice signal PCM multiplexing method is applied. It is a block diagram shown. 1 to 3 ... Call road board, 4 to 6 ... GND detection circuit, 7 to 9
...... Timer, 10 to 12 ...... Analog voice signal line, 13 to 15
...... A / D converter, 16 to 18 ...... Gate, 19 to 21 ...... Field effect transistor, 22 ...... Common control panel, 23 ...... Grand, 24 ...... Multi frame generation circuit, 25 ...... PCM line.

Claims (1)

(57) [Claims] 1. A common control board and a plurality of speech path boards are provided,
In a PCM-30 channel multiplex conversion device that converts a switch signal and a voice signal into PCM to multiplex 30 channels, by inserting an A / D converter that encodes an analog voice signal and outputs it as a PCM voice signal, A GND detection circuit that detects a ground level signal given from the common control board, and a block of a PCM audio signal that is sent out after the communication path board is inserted and before the A / D converter starts normal operation. The timer that generates the output and the PCM of the A / D converter based on the output of this timer
It is equipped with a gate circuit that blocks audio signals, and a field effect transistor that multiplexes and outputs the PCM audio signal from the gate circuit when the output terminal is wired or connected to the other output terminals of the speech path board. PC of audio signal characterized in that the output of PCM audio signal is blocked for a certain time when the roadbed is inserted
M multiplexing method.