JPS5945733A - Pcm terminal station - Google Patents

Abstract

PURPOSE:To prevent the reduction in the level, by detecting a voice channel disc not required and not mounted, and outputting a PCM signal from a received logical disc to the voice channel disc as a transmission signal of the channel as it is. CONSTITUTION:When a PCM terminal station is connected in a loop, a timing signal changeover circuit 1 outputs switchingly a received timing signal from a received timing generating circuit 22. This signal is fed to a PCM signal selecting circuit 15 as a selecting control signal via a voice channel disc 3. When the voice channel disc is mounted, the received timing signal to the voice channel disc 3 is fed to the PCM signal selecting circuit 15, and when the disc is not mounted, that is, the voice channel disc 4 is not loaded, no selecting control signal is supplied. Then, when the disc is not loaded, a PCM signal corresponding to the channel from a separate circuit 21 is multiplexed in time division and outputted as a transmitted PCM signal Tx at a combiner circuit 13 via the PCM signal selecting circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an I'CM terminal station configured to be usable not only for two-way use but also for one-to-N loop type transmission.

FIG. 1 shows the configuration of an example of a PCI terminal station according to the prior art, which is mainly designed to be used in opposite directions.

That is, the PCM terminal station consists of a reception logic board 2, a transmission logic board 1, and voice channel boards 3 and 4 for n channels (only two are shown in this example). The time division multiplexed PCM signal RX from the other party's P (Ji terminal station) is separated into a PCM signal compatible with the audio channel board by the separate circuit 21 within the reception (if logic board), while the reception timing generation circuit 22 determines the reception timing. A signal is generated.The PCM signal, which has been separated to correspond to the g-voice channel board, is converted into audio by sequentially passing through a D/A converter, filter, amplifier, etc. within the audio channel board. The audio input to the audio channel board is converted into a PCM signal by successively passing through an amplifier, a filter, and an A/D converter, and then is converted into a PCM signal in the transmission logic board 1. The signals are time-division multiplexed and combined by the combiner circuit 15 and then transmitted to the other party's PCM terminal station as a transmission PCM signal TX asynchronously with the reception.The transmission timing generation circuit 12 generates a clock signal from the clock generation circuit 1□. If the combiner circuit 13 and the A/D converter in the audio channel board are controlled by this transmission timing signal, the transmit PCM signal TX will be transmitted from the combiner circuit 15 to the audio channel board. Corresponding PCM signals are obtained as time-division multiplexed signals.

FIG. 2 shows a situation in which PCM terminal stations constructed in this manner are used facing each other.

PCM terminal stations 5 and 6 are installed at point A and point B, respectively, and these PCM terminal stations 5 and 6 are connected by a transmission line 7, but problems arise especially when they are used facing each other. It has become something that does not exist. However, when three or more points are connected in a loop or the like, problems occur. FIG. 3 shows an example of a connection mode in such a case. According to this, A with point B as a relay point.

When connecting points C using transmission lines 12 and 13,
There is only one PCM terminal station at point A and point C, respectively8.
However, two PCM terminal stations are required at point B, and a connection is established between these two PCM terminal stations 9 and 10 at the audio level.

In the illustrated case, points A and a' at point B, C at point B and C' at point C, and b at the joining point and b' at point C each indicate that they are communicating, but among these, No particular problem arises in the former two cases. However, communication between point b at point A and b' at point C is carried out via PCM terminal stations 9 and 105, and the connection between PCM terminal stations 9 and 10 is at the audio level as shown in b''. It is necessary to do so.

In other words, since conventional PCM terminal stations are configured primarily for point-to-point use, when connecting three or more points, a voice channel board that is originally unnecessary for the service is needlessly required. This is disadvantageous, and there are cases where the connection is made at the voice level even if it is L, which inevitably causes a deterioration in the communication quality, which has been a problem. By the way, when connecting three or more points, it is conceivable to connect them in a loop, but the reality is that a PCM terminal station suitable for a loop connection has not yet been realized. If possible, it is desired to realize a PCM terminal station that can be used not only for opposite use but also for loop connection.

Therefore, it is an object of the present invention to provide a PCM terminal station which can be used not only for two-way use but also for loop connection, and which does not require connection at the audio level.

For this purpose, the present invention focuses on the fact that the voice channel board corresponding to each channel is removably installed in the PCM terminal station, and detects when a certain voice channel board is not installed because it is unnecessary. , the PCM signal from the receiving logic board for that audio channel board is directly outputted from the sending logic board as the transmitting PCM signal for that channel.

The present invention will be explained below with reference to FIGS. 4 and 5.

FIG. 4 shows the configuration of an example of a PCM terminal station according to the present invention, and according to this, the transmission logic board 1 is newly provided with a timing signal switching circuit 111 and a PCM signal selection circuit 15. ing.

That is, when connecting PCM terminal stations in a loop, the timing signal switching circuit 1. is configured to switch and output the reception timing signal from the reception timing generation circuit 22, and the combiner circuit 15 and the A/D converter in the audio channel board are controlled by the reception timing signal. By the way, the timing signal switching circuit 111
The reception timing signal from the PCM signal selection circuit 15 is given to the PCM signal selection circuit 15 as a selection control signal after passing through the audio channel board. If an audio channel board is installed, the reception timing signal for that audio channel board is given as is to the PCM signal selection circuit 15, but if it is not installed, it is not given.

That is, the PCM signal selection circuit 15 is controlled to be switched in a predetermined manner depending on whether an audio channel board corresponding to each channel is installed or not. The PCM signal from the A/D converter, if implemented, is also
If not implemented, the PCM signals corresponding to the channels from the separate circuit 21 are time-division multiplexed via the PCM signal selection circuit 15 to the combiner circuit 1 to separate the transmitted PCM signal signal. It is. Detection of whether or not an audio channel board is installed is not limited to the above example, but in any case, if a certain audio channel board is not installed, the PCM from the receiving logical board for that audio channel board is detected. The signal is time-division multiplexed as a PCM signal to be transmitted as is, and is treated in the same way as a PCM signal from an installed audio channel board.

FIG. 5 shows a situation where PCM terminal stations according to the present invention are installed at three points and these points are connected in a loop. P according to the present invention is placed at points A, B, and C, respectively.
CM terminal stations 1.4, 15, and 16 are installed, and these are connected in a loop by transmission lines 17, 18, and 19, and the PCM terminal station 14 functions as a mask. a at point A and a' at point B flk
, b at point A and b' at point C, C at point B and a at point C
′ shows the signal flow when each communication is in progress.

As shown in the figure, PCM terminal stations 14, 15, and 16 transmit PCM signals from c', b, and a' as they are, respectively.
It can be seen that the signal is now transmitted as a CM signal to the next PCM terminal station. Note that the frame memory 20 inserted into the transmission path 17 is for time adjustment, and it is sufficient if it is inserted into any one of the transmission paths 17, 18, and 19.

The present invention is as described above, but by adding a few simple circuits to the PCM terminal station and configuring it as described above, it is a standard that can be used not only for opposite use but also for loop connection. A PCM terminal station with the following configuration can be easily obtained. In the case of dual use, the timing signal switching circuit may be set to output the timing signal from the transmission timing generation circuit, and the PCM signal selection circuit may be set to select and output the PCM signal from the audio channel board. be.

As explained above, in the present invention, when making a loop connection, the sending timing signal is used as the receiving timing signal, and depending on whether or not the audio channel board is installed, the PCM signal to be transmitted is sent from the audio channel board. It is either from the receiving logic board or from the receiving logic board. Therefore, in the case of the present invention, by simply adding a simple switching circuit or a selection circuit, it can be used not only for opposite use but also for loop connection, and the communication quality is improved because the connection is not made at the voice level. This has the effect of improving the

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of a PCM terminal station according to the prior art, FIG. 2 is a state diagram when the PCM terminal stations are used facing each other, and Section 3 shows the configuration of an example of a PCM terminal station according to the prior art. FIG. 4 is a connection state diagram of an example of a PCM terminal station when connecting points. FIG. 4 is a configuration diagram of an example of a PCM terminal station according to the present invention. It is a state diagram when points are connected in a loop. l...Transmission logic board, 12...Transmission timing generation circuit, 13...combiner circuit, lll...timing signal switching circuit, l...PCM signal selection circuit, 2.
...Reception logic board, 21...Separate circuit, 22...
・Reception timing generation circuit, 3.4...Audio channel board agent Patent attorney Masami Akimoto

Claims (1)

[Claims] Based on the reception timing signal created from the time-division multiplexed PCM signal from the other party's PCM terminal station, the channel-compatible PCM signal constituting the time-division multiplexed PCM signal is distributed to the channel-compatible audio channel board and output as audio. In the PCM terminal station, the input audio-compatible PCM signal obtained from the channel-compatible audio channel board is time-division multiplexed under the control of the transmission timing signal and sent to the other party's PCM terminal station. The PCM signal from the audio channel board is detected by detecting whether it is installed or not for each channel, and outputting the output related to the detection to control the PCM signal selection circuit.
It is possible to predetermined select one of the PCM signals to be sent to an audio channel board and obtain it as a PCM signal corresponding to the channel to be transmitted, and it is also possible to obtain a reception timing signal as a transmission timing signal by a timing signal switching circuit. A PCM terminal station characterized by its configuration.