JP2581266B2 - Multiplexer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a PCM multiplexing apparatus, and particularly to a PCM multiplexing apparatus, particularly between a two bit-steel transmission line and a digital relay line other than a bit-steel transmission line such as a high-speed digital line. The present invention relates to a multiplexer that relays and guarantees a signaling position in a voice PCM signal.

[Conventional technology]

Conventionally, a first voice PCM signal input to a multiplexing device of this type from a first bit-steel transmission line is configured as a multiframe, and the least significant bit of each channel of a specific frame, typically the Signaling bits are embedded in 8 bits (for example, Yamashita, "Easy Digital Transmission", 2nd edition, 2nd edition, pp27-pp31, Ohmsha, April 5, 1989). In this multiplexer, the signaling bits are first separated from the voice PCM signal channel. The separated signaling bits are relayed and transmitted on out-channels other than the voice PCM signal channel, and the voice PCM signal from which the signaling bits have been separated is transmitted to the TSI unit (Time
Slot Interchanger = time slot interchanger, for example, “reproduced, pp102, FIG. 3.23”), and after being subjected to relay processing such as separation / multiplexing, is retransmitted as a second PCM audio signal to the second bit steal transmission path. At that time it had been inserted again. The multiplexed first digital signal is input from the first digital trunk line to the multiplexer. After the first digital signal is frame-synchronized, the first digital signal is separated and multiplexed together with the voice PCM signal by time slot replacement by the TSI unit. And
One of the separated and multiplexed multiplexed signals is sent to a second digital trunk line as a second digital signal with a frame pattern added thereto.

[Problems to be solved by the invention]

The above-described conventional multiplexing apparatus has a disadvantage that a circuit for time slot management of signaling bits is complicated because the signaling bits are once separated from the PCM audio signal channel to perform demultiplexing / multiplexing processing.

[Means for solving the problem]

A first voice PCM signal composed of a multi-frame from a first bit-steel transmission line and having a signaling bit assigned to a least significant bit of a specific frame, and a multiplexed first digital signal from a first digital trunk line; A second voice PCM signal, which is formed into a multi-frame by separating and multiplexing the signal and is bit-stealed, is transmitted to a second bit-steel transmission line, and the multiplexed second digital signal is converted to a second digital signal. A multiplexing device for transmitting to a trunk line, a multi-frame synchronizing means for multi-frame synchronizing the first voice PCM signal from the first bit steal transmission line in units of a fixed number of frames; Least significant bit of each voice channel excluding the signaling bits of the first voice PCM signal Channel frame synchronization pattern inserting means for replacing the packet with a predetermined channel frame synchronization pattern; separating and multiplexing a signal input from the channel frame synchronization pattern inserting means for each audio channel signal; The first digital signal obtained is relayed by being separated and multiplexed in synchronization with the signal of the voice channel from the channel frame synchronization pattern insertion means, and the first multiplexed signal that has been bit stealed is combined with the first multiplexed signal. Separation / multiplexing means for generating a second multiplexed signal, and channel frame synchronization processing means for detecting the channel frame synchronization pattern of the first multiplexed signal and performing channel frame synchronization for matching the position of the channel frame synchronization pattern. When,
A frame synchronization pattern adding means for adding a predetermined frame synchronization pattern to the channel frame synchronized signal to generate the second audio PCM signal.

〔Example〕

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

The embodiment will be described with reference to signal configuration diagrams shown in FIGS. 2 (a), 2 (b) and 2 (c).

Here, for the sake of convenience, the voice PCM signal transmitted through the bit steal transmission lines 2 and 4 encodes one channel of voice at 64 kbit / s in accordance with the CCITT recommendation (G.700 series) and outputs one frame / frame. It is assumed to be configured with 24 channels, 1 multiframe / 12 or 24 frames (see FIGS. 2 (a) and 2 (b)). One frame is 193 bits / 125 μs, and bit repetition is 1.544 Mbits / s. One channel is composed of 8 bits, and one frame bit is added to the head of each frame. The signaling bit is provided (bit stealed) in the least significant bit, that is, the eighth bit of each channel of a specific frame, for example, the sixth, twelfth, eighteenth, and twenty-fourth frames of one multiframe.

In the multiplexing apparatus 100, a frame synchronization processing unit receives data from the bit-steel transmission line 2 on the receiving side.
Reference numeral 102 synchronizes frames every 12 or 24 frames depending on the configuration of the multi-frame. Then, the received data is output to the channel frame pattern insertion unit 103 in synchronization with the reference phase in the apparatus, and when the received data is composed of 12 frames / multiframe, the data is output at the time of the first frame of the first multiframe of two multiframe periods. , 24 frame / multiframe configuration, the receiving side multiframe synchronization signal 104 is output to the channel frame pattern insertion section 103 at the time of the first frame. Here, the voice PCM signal having the 12-frame / multi-frame configuration is also pseudo-multi-frame-synchronized with the 24-frame / multi-frame configuration.

Next, the channel frame pattern insertion unit 103
Bit / s voice PCM voice channel (each voice channel) The 8th bit voice signal other than bit-steel signaling, replacing 20 bits per multiframe with a predetermined unique frame synchronization pattern, ie, each channel (See FIG. 2 (c))
It is transmitted to the TSI section (Time Slot Interchanger = Time Slot Interchanger) 105. Although the noise is slightly increased by using the eighth bit of the audio PCM signal as the channel frame synchronization signal, there is no practical problem.

In the TSI unit 105, the input voice PCM signal is replaced with a time slot in units of one voice channel, and a relay process for separating / multiplexing each voice channel is performed. Then, according to the instruction of the time slot control memory in the TSI unit 105, the output is output to the trunk line 3 or the bit-steel transmission line 4 on the transmission side.
And send data.

When transmitting data to the trunk line 3, a trunk line frame pattern is added by the trunk line frame pattern adding unit 108.

When transmitting transmission data to the bit-steel transmission path 4 on the transmission side, the channel frame synchronization processing unit 106 individually performs frame synchronization processing on audio channel signals having different input phases for each audio channel. Then, all audio channels are phase-synchronized with the transmission-side multi-frame synchronization signal 109, which is a 24-frame multi-frame synchronization signal transmitted from the frame synchronization pattern adding unit 107, and output.

The frame synchronization pattern adding unit 107 adds a frame pattern in accordance with the frame specification of the bit steal transmission path 4.

Further, the data received from the trunk line 1 is frame-synchronized by the trunk line frame period processing unit 101, synchronized with the reference phase in the device, transmitted to the TSI unit 105, and then transmitted from the bit steel transmission line 2. Like the received data,
Processing for transmitting data to the trunk line 3 or the bit steal transmission line 4 is performed.

As described above, in the present embodiment, the received data input from the bit-steel transmission path 2, that is, the first voice
Channel frame pattern insertion section 103 for PCM signals
Replaces the eighth bit other than bit-steel signaling with a unique channel frame synchronization pattern in 24 frame periods, ie, 20 audio signal bits per multiframe / audio channel. Then, at the time when the transmission data, that is, the second PCM audio signal is transmitted to the bit steel transmission line 4, the channel frame synchronization processing unit 106
Channel frame synchronization is individually performed for each audio channel by the channel frame synchronization pattern added to the eighth bit of each audio channel, and the signal bits of all audio channels are matched with the transmission frame synchronization phase for the bit-steel transmission line 2. Accordingly, switching of the PCM audio signal in units of channels can be easily performed. As described above, the multiplexing device according to the present embodiment can perform relay processing by demultiplexing / multiplexing while adding signaling bits to the voice channel of the voice PCM signal, so that no special time slot management for the signaling bits is required. And the multiplexing device is simplified.

〔The invention's effect〕

As described above, according to the present invention, the time slot management of the signaling bit in the multiplexing device can be performed using the same voice PCM channel, so that the circuit configuration can be simplified and the effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 (a), (b) and (c) are signal configuration diagrams. 1,3 ... trunk line, 2,4 ... bit steel transmission line, 10
0: multiplexing device, 101: trunk line frame synchronization processing unit, 102: frame synchronization processing unit, 103: channel frame pattern insertion unit, 104, 109: frame synchronization signal, 1
05: TSI unit, 106: Channel frame synchronization processing unit, 10
7: Frame synchronization pattern adding unit, 108: Trunk line frame pattern adding unit.

Claims (1)

(57) [Claims] 1. A first voice PCM signal in which a multi-frame is formed from a first bit-steel transmission line and a signaling bit is assigned to a least significant bit of a specific frame and multiplexed from a first digital trunk line. First
The second voice is demultiplexed and multiplexed into a multi-frame and bit stealed.
A multiplexing device for transmitting a PCM signal to a second bit-steel transmission line and transmitting a multiplexed second digital signal to a second digital trunk line, comprising: A multi-frame synchronization unit that performs multi-frame synchronization with respect to one audio PCM signal in units of a fixed number of frames; and a maximum of each audio channel excluding the signaling bits of the first audio PCM signal with multi-frame synchronization. Channel frame synchronization pattern insertion means for replacing lower-order bits with a predetermined channel frame synchronization pattern; and a signal input from the channel frame synchronization pattern insertion means is separated and multiplexed for each audio channel signal. Converting the first digital signal taken into the channel frame synchronization pattern A demultiplexing / multiplexing unit that performs a relay process by demultiplexing / multiplexing in synchronization with the signal of the voice channel from the insertion unit to generate a first multiplexed signal and a second multiplexed signal that are bit stealed; Channel frame synchronization processing means for detecting the channel frame synchronization pattern of the first multiplexed signal and performing channel frame synchronization for matching the position of the channel frame synchronization pattern, and a predetermined frame synchronization pattern for the channel frame synchronized signal And a frame synchronizing pattern adding means for generating the second audio PCM signal by adding a second audio PCM signal.