CN1134634A - PCM digital basic group transmission system and its transmission method - Google Patents
PCM digital basic group transmission system and its transmission method Download PDFInfo
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- CN1134634A CN1134634A CN 95111608 CN95111608A CN1134634A CN 1134634 A CN1134634 A CN 1134634A CN 95111608 CN95111608 CN 95111608 CN 95111608 A CN95111608 A CN 95111608A CN 1134634 A CN1134634 A CN 1134634A
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Abstract
The present invention relates to short-distance and small-capacity PCM digital basic group transmission system and transmission method. The transmission system of the present invention includes HDB3/NRZ code type convertor, elastic memory, synchronous clock extractor circuit, line signal extractor circuit, low-speed interfaces connected to the elastic memory, microprocessor and system clock circuit, and every interface includes U-interface, ADPCM coder, output interval adjustor circuit, input interval adjustor circuit and ADPCM decoder. The PCM digital basic group after being processed via above said circuits may be transmitted through common telephone wires.
Description
The present invention relates to a kind of PCM digroup transmission system, relate in particular to short-distance and medium-distance, low capacity PCM digroup transmission system.The present invention also provides a kind of PCM digroup transmission system used transmission method.
At present, realize the engineering transmission of short-distance and medium-distance PCM basic group signal, often continue to use remote, large capacity digital group road transmission equipment, adopt the high-capacity optical fiber transmission system of high order block, for example, the transmission system of fourth order group, its information is captured rate up to 139.264Mbit/s, the altogether multiplexing basic group PCM signal of 64 2.048Mbit/s.For as long as transmit the business of a PCM basic group signal, in fact only utilized 1/64 (1/4 of this transmission system ability
N-1, N is the number of times of high order block).This system is that the PCM group signals with 2.048Mbit/s is a unit in accordance with regulations after the form time division multiplexing, becomes the high-speed high capacity transmission link, is sent to far end system by optical device and light modulation through optical fiber.On the other hand, the light modulating signal that far-end is sent is reduced into the non return to zero signal of telecommunication by optical device, realizes that through signal processing restoring all by time-division mode and prescribed form is the signal flow of unit with 2.048Mbit/s basic group (perhaps other low order group).In above-described transmission and reception group road group, select a pair of PCM basic group, carry out the transmission of low capacity PCM basic group signal.Obviously, can cause the huge wasting of resources with remote, large capacity digital group road transmission system.Moreover, between the two places that do not have high capacity transmission system originally, specially lay optical cable for transmission low capacity primary block road (as a PCM basic group signal), build transmission equipment, not only the cycle long, and cost height.
The object of the present invention is to provide a kind of low capacity PCM primary block road transmission system and transmission method thereof that is applicable to short-distance and medium-distance, the construction cost of this system is low, the cycle short, installs and open fast and convenient.
PCM digroup transmission system of the present invention, this PCM digroup comprises telephone path signal, frame synchronizing signal and line letter signal signal, described PCM digroup transmission system comprises HDB3/NRZ code conversion circuit and the elastic storage device that links to each other with described HDB3/NRZ code conversion circuit, the Signals ﹠ Systems clock signal synchronised of described elastic storage device output, it is characterized in that, also comprise:
Clock, frame synchronization, multi-frame synchronous extraction circuit are used for extracting clock, frame synchronization, multiframe alignment signal from the PCM signal flow of HDB3 sign indicating number type or from the PCM signal flow of the NRZ sign indicating number type of described HDB3/NRZ code conversion circuit output;
Line signalling extracts circuit, links to each other with described clock, frame synchronization, multi-frame synchronous extraction circuit with described elastic storage device, is used for extracting the line letter signal signal of NRZ sign indicating number type PCM signal;
The low speed line interface that at least one described elastic storage device links to each other, each line interface comprises
The u interface of one ISDN is used for ADPCM voice signal and signaling-information, monitoring alarm signal are delivered to telephone line together and sent, and from the low speed signal of telephone line reception from the identical content of far-end;
Adpcm encoder links to each other with described elastic storage device, is used for shortening the PCM signal pressure of NRZ sign indicating number type into the ADPCM low speed signal;
Output time solt is adjusted circuit, links to each other with described adpcm encoder, is used for the signal format that the u interface that described ADPCM low speed signal is adjusted to described ISDN is required; The output of described output time solt adjustment circuit is connected to the u interface of described ISDN;
Input time slot is adjusted circuit, links to each other with the u interface of described ISDN, is used for the signal of described u interface output is adjusted to the signal format that ADPCM decoder requires; With
ADPCM decoder is adjusted circuit with described input signal time slot and is linked to each other, and is used for compressed ADPCM low speed signal is decoded into the PCM signal of NRZ sign indicating number type.
The framing circuit links to each other with described a plurality of low speed line interfaces, and the PCM signal flow that is used for frame swynchronization code, multi-frame synchronous code and line signalling sign indicating number are inserted into NRZ sign indicating number type goes;
NRZ/HDB3 code conversion circuit links to each other with described framing circuit, is used to export the PCM signal flow of HDB3 sign indicating number type;
Microprocessor, link to each other respectively with above-mentioned each circuit, be used to specify the signal of the different speech channels in the different low speed line interface transmitting-receiving PCM basic group code streams, receive the line letter signal signal that described line signalling extracts all speech channels of circuit, respectively they are delivered to u interface with the pairing described ISDN of described speech channel, and from the signal flow that the u interface of described ISDN is exported, extract line letter signal signal from far-end, deliver to described framing circuit; With
System clock circuit links to each other respectively with above-mentioned each circuit, is used to the clock signal of system, synchronizing signal and the timing controling signal that provide unified.
The present invention also provides a kind of sending method of PCM digroup transmission system, comprising:
The PCM signal transformation of HDB3 sign indicating number type is become the PCM signal of NRZ sign indicating number type;
From the PCM signal of the PCM signal of HDB3 sign indicating number type or described NRZ sign indicating number type, extract clock, frame synchronization and multiframe alignment signal;
From the PCM signal of described NRZ sign indicating number type, extract signaling-information and relevant monitoring alarm signal with the clock that extracts, frame synchronization and multiframe alignment signal;
The PCM signal of described NRZ sign indicating number type is delivered to adpcm encoder, be compressed into the ADPCM low speed signal;
Described ADPCM low speed signal is carried out the time slot adjustment, be adjusted to the u interface that signal format that the u interface of ISDN requires is delivered to ISDN again;
The PCM signal of described NRZ sign indicating number type is delivered to the u interface of a plurality of ISDN with the described line letter signal signal that extracts, export telephone wire to by the u interface of ISDN.
The method of reseptance of PCM digroup transmission system of the present invention comprises:
U interface by a plurality of ISDN receives PCM signal and line letter signal signal from far-end from telephone wire;
The signal that the u interface of each ISDN is exported carries out the time slot adjustment earlier, makes it to become the form of ADPCM decoder requirement;
Delivering to ADPCM decoder deciphers, form a time-multiplexed PCM signal flow that contains speech channel, the described line letter signal signal that will receive with system clock, frame synchronization and multiframe alignment signal is inserted in the described PCM basic group signal, carries out framing, forms the PCM basic group signal of NRZ sign indicating number type;
The PCM basic group signal of NRZ sign indicating number type is transformed into the PCM basic group signal of HDB3 sign indicating number type.
PCM digroup transmission system provided by the invention and method of sending and receiving thereof can carry out the short-distance and medium-distance transmission to low capacity PCM signal through ordinary telephone line.
Describe the present invention in detail below in conjunction with accompanying drawing.
Fig. 1 is the frame assumption diagram of the PCM basic group signal that transmits of the present invention;
Fig. 2 is the structure of time slot figure of the PCM basic group signal that transmits of the present invention;
Fig. 3 is the block diagram of PCM basic group transmission system of the present invention;
Fig. 4 is the oscillogram of PCM bipolarity rz signal;
Fig. 5 is the oscillogram of PCM non-return-to-zero signal;
Fig. 6 is the PCM basic group code stream format chart of elastic storage device output;
Fig. 7 is the format chart that compressed adpcm code flows;
Fig. 8 and Fig. 9 are through the adjusted adpcm code stream format of time slot figure;
Figure 10 is the flow chart of PCM digroup sending method of the present invention;
Figure 11 is the flow chart of the method for reseptance of PCM digroup of the present invention;
Figure 12 is the block diagram of another embodiment of transmission system of the present invention.
At first, the PCM basic group signal that will transmit the present invention is done a simply description.The PCM basic group signal is made of high and low level (representing 1/0 respectively) signal a string, each high level or low level are called 1 bit, and per 8 bits constitute a time slot, transmit one road telephone path signal or signaling-information etc., per 32 time slots are formed a frame, and per 16 frames constitute a multi-frame.See also Fig. 1 and Fig. 2, they show the frame structure of PCM basic group.Each multi-frame has 16 frames ((see figure 1) of F0-F15), every frame has 32 time slots ((see figure 2) of TS0-TS31), time slot TS0 in wherein every frame is a frame alignment time slot, and time slot TS16 is the signalling time slot, and time slot TS1-TS15 and TS17-TS31 are respectively the time slot that transmits speech channel 1-30 signals.Each time slot all comprises 8 bits.The line letter signal signal that the time slot TS16 of different frame represents in a multi-frame is different, line signalling time slot F0TS16 for the first frame F0, its preceding four is the multi-frame synchronous code, four of backs are multi-frame monitoring alarm sign indicating number, its preceding four of the line signalling time slot F1TS16 of the second frame F1 are the line signalling sign indicating number of speech channel 1, and back four are the line signalling sign indicating number of speech channel 16; Its preceding four of the line signalling time slot F2TS16 of the 3rd frame F2 are the line signalling sign indicating number of speech channel 2, and back four are the line signalling sign indicating number of speech channel 2, and back four are the line signalling sign indicating number of speech channel 17; And the like, until preceding four of the line signalling time slot F15TS16 of the 16 frame F15 are the line signalling sign indicating number of speech channel 15, back four are the line signalling sign indicating number of speech channel 30.
Describe an embodiment of PCM digroup transmission system of the present invention in detail below in conjunction with Fig. 3.As shown in Figure 3, this PCM digroup transmission system is a two-way system, and the PCM basic group signal can be sent to far-end by ordinary telephone line after this system, also can receive the basic group signal that far-end is sent here from telephone wire.Native system generally links to each other with the exchange or the transmission equipment of local side by coaxial cable or twisted-pair feeder with TO via transmission transformer TI, and the signal code type that transmits on its circuit is HDB3.Native system also links to each other with the transmission system that is positioned at far-end by many ordinary telephone lines.
Usually, PCM basic group signal before transmission is a bipolarity rz signal (the PCM basic group signal of HDB3 sign indicating number type) (as shown in Figure 4), this signal is delivered to HDB3/NRZ code conversion circuit 1 after transmission transformer TI coupling, this code conversion circuit 1 is transformed into the PCM basic group signal of NRZ sign indicating number type as shown in Figure 5, i.e. non-return-to-zero signal to the bipolarity rz signal.The PCM signal of the NRZ sign indicating number type of code conversion circuit 1 output is delivered to clock, frame synchronization and multi-frame synchronous extraction circuit 2, extracts clock, frame synchronization and multiframe alignment signal in the PCM signal in clock and synchronous extraction circuit 2.Certainly, clock, frame synchronization and multi-frame synchronous extraction circuit 2 also can make zero from the bipolarity without conversion and extract clock, frame synchronization and multiframe alignment signal the letter.The NRZ sign indicating number type PCM basic group signal of code conversion circuit 1 output is delivered to line signalling with the clock, frame synchronization and the multiframe alignment signal that extract circuit 2 outputs and is extracted circuit 4, line signalling extracts circuit 4 and extracts line letter signal signal and monitoring alarm signal among the 16th time slot TS16 in each above-mentioned frame according to clock, frame synchronization and multiframe alignment signal from the PCM basic group signal, and delivers to microprocessor 10.
The PCM signal of the NRZ sign indicating number type of 3 pairs of inputs of elastic storage device is handled, and the PCM signal of output and system clock and system-frame synchronizing signal synchronised, still contains all information in the original PCM signal in the signal flow of its output.Behind elastic storage device 3, be connected to 8 low speed line interface 5A, 5B...5H.
Each interface includes u interface 53, input time slot adjustment circuit 54 and the ADPCM decoder 55 of adpcm encoder 51, output time solt adjustment circuit 52, ISDN among low speed line interface 5A-5H.Adpcm encoder 51 receives the pcm stream of the NRZ sign indicating number type of elastic storage device 3 outputs.The u interface of ISDN is a two-way device, its input BX can and deliver to ordinary telephone line by the signal that the signal of sending here on the Microprocessor Interface is transformed into 2B1Q sign indicating number type (2 bits, 4 level) together with the signal in two 8 bit time slots of this interface of input and transfer out, can also receive the signal of 2B1Q sign indicating number type from ordinary telephone line, the signal in two 8 bit time slots is recovered out to deliver to the BR output and delivers to the Microprocessor Interface output by the signal that the other side sends here by Microprocessor Interface.This pcm stream as shown in Figure 6, each time slot TS1-TS15, TS17-TS31 includes the information of speech channel 1-30 respectively.In the present embodiment, used 8 low speed line interface 5A-5H, these 8 low speed line interface 5A-5H can transmit 30 tunnel speech channels, and the multipotency of each low speed line interface transmits 4 tunnel speech channels.Which 4 tunnel word each low speed line interface transmits can be controlled by microprocessor 10, as 1-4 tunnel speech channels that comprise among time slot TS1-TS4 can being transmitted by low speed line interface 5A, 5-8 tunnel words that comprise among time slot TS5-TS8 are transmitted by low speed line interface 5B, and the like.Because each time slot has 8 bits, then 4 time slots add up to 32 bit data, and as mentioned above, interface can only transmit 2 group of 8 bit information, and therefore, this four road signal at first should compress.As shown in Figure 3,4 tunnel speech channel information in the pcm stream of this NRZ sign indicating number type are delivered to adpcm encoder 51 earlier and are compressed.Situation according to present embodiment, the compression ratio of this adpcm encoder 51 is 1/2 times, signal is become to comprise 4 bits in each time slot by original 8 bit compression of each time slot, the information A 0 ', the A1 ' that comprise 4 bits as the TS0 among Fig. 7, TS1, each time slot of TS2...TS31. TS0, TS1...TS31 respectively ... A31 ', 4 of the residues in the time slot are invalid signals.The u interface 53 that the adpcm code of this kind form stream also is not suitable for directly sending into ISDN sends, and it must pass through the time slot adjustment.As shown in Figure 3, signal slot is adjusted the receptible adpcm code of u interface that circuit 52 will adpcm code stream shown in Figure 7 be adjusted to Fig. 8 or ISDN shown in Figure 9 and is flowed, be about to the information (as Fig. 8) of synthetic one 8 bit of speech channel information sets of two 4 adjacent bits, the information (as Fig. 9) of perhaps 44 adjacent bit speech channel information sets being synthesized one 16 bit.Because TS0 and TS16 are respectively frame synchronization and line signalling time slot as previously mentioned, therefore, as can be seen from the figure, when time slot was adjusted, the content (information) that this TS0 and TS16 time slot are comprised can not transmit.The u interface of ISDN will become the signal of 2B1Q sign indicating number type to export telephone wire to through coupling transformer T through the conversion of signals that adjusted signal and microprocessor are sent to be sent to far-end.
Described native system above to speech channel Signal Processing and transmission, owing to also include line letter signal signal in the PCM signal, this signal extracts circuit 4 by line letter signal signal and extracts, and delivers to microprocessor 10.In the present embodiment, microprocessor 10 is directly delivered to the line signalling sign indicating number of the telephone path signal that u interface transmitted of this ISDN and monitoring alarm sign indicating number in the u interface of ISDN that low speed line meets device 5A-5H respectively.U interface by ISDN is sent to far-end it and after 28 signal combination of its input BR input.
Described the structure that sends part in the PCM digroup transmission system above, the u interface of ISDN is a kind of bilateral device, and it also can receive the information of sending from the transmission system through same structure of far-end from telephone wire.As shown in Figure 3, the u interface 53 of ISDN sends the information that receives to input time slot by its BR end and adjusts circuit 54, this input time slot is adjusted circuit 54 and is finished and the 51 corresponding work of output time solt adjustment circuit, promptly carry out inverse time crack adjustment, decipher by ADPCM decoder 55 again, adpcm code stream is translated into pcm stream.
Framing circuit 6 receives the signal of the ADPCM decoder 55 of each low speed line interface 5A-5H, under the control of microprocessor 10, these information are reformulated frame and multi-frame form, and insert frame swynchronization code, multi-frame synchronous code and microprocessor 10 in the relevant position from line signalling sign indicating number and monitoring alarm sign indicating number that the u interface 53 of each ISDN receives, be reduced into pcm stream shown in Figure 6.Framing circuit 6 is delivered to NRZ/HDB3 code conversion circuit 7 with pcm stream subsequently, code conversion circuit 7 becomes the PCM signal transformation of NRZ sign indicating number type the PCM signal (bipolarity rz signal) of HDB3 sign indicating number type thus, after receiving function is finished in transmission transformer TO output.In this transmission system, the line signalling information in every frame (being included among the time slot TS16) is to extract separately, directly delivers to by microprocessor 10 to transmit in the u interface of ISDN, and it is different with other telephone path signal, without ADPCM coding or decoding.In addition, in native system, frame swynchronization code and multi-frame synchronous code can not transmit, and whole system itself has a clock system, is used to control each circuit coordinates work, and unified clock signal of system and various timing signal is provided.
As mentioned above, in the present embodiment, 8 low speed lines have been used, to transmit 30 tunnel words.If when the speech channel of transmission was less than 30 the tunnel, so, the low speed line interface can correspondingly reduce.For example only transmit 4 speech channels, only need a low speed line interface.If transmit 8 speech channels, need two low-speed interfaces.
We can also draw following PCM digroup transmission method from this system, and it comprises sending method and method of reseptance.
Earlier sending method is described referring to Figure 10.At the PCM signal (non-return-to-zero signal) of step 101 with PCM signal (bipolarity rz signal) the conversion NRZ sign indicating number type of HDB3 sign indicating number type; In step 102, from the PCM signal of the PCM signal of HDB3 sign indicating number type or NRZ sign indicating number type, extract clock, frame synchronization and multiframe alignment signal; To 103, from the PCM signal of NRZ sign indicating number type, extract line letter signal signal and monitoring alarm signal with the clock, frame synchronization and the multiframe alignment signal that extract; 104, the PCM signal of NRZ sign indicating number type is delivered to adpcm encoder then, be compressed into low speed signal; Enter 105, the ADPCM low speed signal is advanced the time slot adjustment, make it to be suitable for the requirement of the u interface of ISDN, at last, 106, deliver to the u interface of ISDN, meanwhile, microprocessor will extract line letter signal signal that circuit obtains and pilot signal from line signalling and will be sent on the telephone wire by the u interface of ISDN, transfer to far end system.
The method of reseptance of PCM digroup transmission system of the present invention can be referring to Figure 11, in step 201, receives ADPCM signal flow and line letter signal signal and monitoring alarm signal from far-end by the u interface of a plurality of ISDN from telephone wire; In step 202, the signal that u interface is exported carries out the time slot adjustment, makes it to become the form of ADPCM decoder requirement, carries out ADPCM decoding 203 then; 204, the line letter signal signal and the monitoring alarm signal of each speech channel that TS0 and TS16 insertion frame swynchronization code, multi-frame synchronous code and microprocessor are sent here in the PCM signal flow that decoding obtains, carry out framing, form the PCM signal of NRZ sign indicating number type, at last, 205, the PCM signal flow of NRZ sign indicating number type is transformed into the PCM stream signal of HDB3 sign indicating number type.
Referring to Figure 12, Figure 12 shows the block diagram of an alternative embodiment of the invention again.Embodiment shown in Figure 12 is that with the difference of embodiment shown in Figure 3 the line letter signal signal transfer approach is different.In the embodiment shown in fig. 3, the line letter signal signal that line signalling extraction circuit 4 extracts is delivered to microprocessor 10, is delivered to the u interface of ISDN again by microprocessor 10.And in the present embodiment, this line letter signal signal is without microprocessor, and directly delivers to the u interface of ISDN.Transmission 30 road telephone path signals as described PCM basic group signal in the embodiments of figure 3, each low speed line interface can transmit 4 road telephone path signals, therefore, in 8 low speed line interface 5A-5H, there is a low speed line interface (being 5H in the present embodiment) only to transmit 2 road telephone path signals, therefore, this low speed line interface 5H still has the time slot capacity of 8 bits not utilize, and can transmit the various signals among the TS16 in the pcm stream of elastic storage device 3 output with it.
Among the low-speed interface 5H in Figure 12, adpcm encoder 501 is except carrying out two speech channels of regulation the ADPCM compression, also TS16 signal in the signal flow of input is carried out transparent transmission, adjust in the circuit 502 that one 8 bit time slots are formed in two speech channels and the TS16 time slot signal takies another 8 bit time slots at time slot, the time slot of these two 8 bits is delivered to u interface BX transmitting terminal.At receiving terminal, the signal of two 8 bit time slots that u interface 503 is sent is delivered to time slot and is adjusted the time slot signal that circuit 504 carries out one of them 8 bit time slots is adjusted to the signal format that two adpcm encoders 505 can accept, and the time slot of another TS16 signal that is sent by far-end is not directly dealt with by adpcm encoder and goes among the TS16 that directly delivers to public signal bus, signal on this signal bus is delivered to framing circuit 6, in the framing circuit, only carry out the insertion of frame swynchronization code, and all signals among the TS16 of reservation input signal.
Claims (7)
1. PCM digroup transmission system, described PCM digroup comprises telephone path signal, frame synchronizing signal and line letter signal signal and monitoring alarm signal, described PCM digroup transmission system comprises HDB3/NRZ code conversion circuit and the elastic storage device that links to each other with described HDB3/NRZ code conversion circuit, the Signals ﹠ Systems clock signal synchronised of described elastic storage device output, it is characterized in that, also comprise:
Clock, frame synchronization, multi-frame synchronous extraction circuit are used for extracting clock, frame synchronization, multiframe alignment signal from the PCM signal flow of HDB3 sign indicating number type or from the PCM signal flow of the NRZ sign indicating number type of described HDB3/NRZ code conversion circuit output;
Line signalling extracts circuit, links to each other with described clock, frame synchronization, multi-frame synchronous extraction circuit with described elastic storage device, is used for extracting the line letter signal signal of NRZ sign indicating number type PCM signal flow;
At least one and the low speed line interface that described elastic storage device links to each other, each line interface comprises
The u interface of one ISDN is used for ADPCM voice signal and signaling-information, monitoring alarm signal are delivered to telephone line together and sent, and from the low speed signal of telephone line reception from the identical content of far-end;
Adpcm encoder links to each other with described elastic storage device, is used for shortening the PCM signal pressure of NRZ sign indicating number type into the ADPCM low speed signal;
Output time solt is adjusted circuit, links to each other with described adpcm encoder, is used for described ADPCM low speed signal is adjusted to the signal format of described u interface requirement; The output that described output time solt is adjusted circuit is connected to described u interface;
Input time slot is adjusted circuit, links to each other with described u interface, is used for the signal of described u interface output is adjusted to the signal format that ADPCM decoder requires; With
ADPCM decoder is adjusted circuit with described input signal time slot and is linked to each other, and is used for compressed ADPCM low speed signal is decoded into the PCM signal of NRZ sign indicating number type.
The framing circuit links to each other with described a plurality of low speed line interfaces, and the PCM signal flow that is used for frame swynchronization code, multi-frame synchronous code and line signalling sign indicating number are inserted into NRZ sign indicating number type goes;
NRZ/HDB3 code conversion circuit links to each other with described framing circuit, is used to export the PCM signal flow of HDB3 sign indicating number type;
Microprocessor, link to each other respectively with above-mentioned each circuit, be used to specify the signal of the different speech channels in the different low speed line interface transmitting-receiving PCM basic group code streams, receive the line letter signal signal that described line signalling extracts all speech channels of circuit, respectively they are delivered to and the pairing described u interface of described speech, and from the signal flow from far-end of described u interface output, extract line letter signal signal, deliver to described framing circuit; With
System clock circuit links to each other respectively with above-mentioned each circuit, is used to the clock signal of system, synchronizing signal and the timing controling signal that provide unified.
2. PCM digroup transmission system as claimed in claim 1 is characterized in that the compression ratio of described adpcm encoder is 1/2, and described low speed line interface has 8.
The sending method of 3 one kinds of PCM digroup transmission systems comprises:
The PCM signal transformation of HDB3 sign indicating number type is become the PCM signal of NRZ sign indicating number type;
It is characterized in that, also comprise:
From the PCM signal of the PCM signal of HDB3 sign indicating number type or described NRZ sign indicating number type, extract clock, frame synchronization and multiframe alignment signal;
From the PCM signal of described NRZ sign indicating number type, extract signal with the clock that extracts, frame synchronization and multiframe alignment signal;
Again the PCM signal of described NRZ sign indicating number type is delivered to adpcm encoder, be compressed into the ADPCM low speed signal;
Described ADPCM low speed signal is carried out the time slot adjustment, and the signal format that is adjusted to the u interface requirement is delivered to u interface again;
The PCM signal of described NRZ sign indicating number type is delivered to a plurality of u interfaces with the described line letter signal signal that extracts, export telephone wire to by u interface.
4. the sending method of PCM digroup transmission system as claimed in claim 3 is characterized in that, the compression ratio of described adpcm encoder is 1/2, and the number of described u interface is 8.
5. the method for reseptance of a PCM digroup transmission system is characterized in that, comprising:
Receive PCM signal and line letter signal signal by a plurality of u interfaces from telephone wire from far-end;
Signal to each u interface output carries out the time slot adjustment earlier, makes it to become the form of ADPCM decoder requirement;
Delivering to ADPCM decoder deciphers, form a time-multiplexed PCM signal flow that contains all speech channels, the described line letter signal signal that will receive with system clock, frame synchronization and multiframe alignment signal is inserted in the described PCM signal, carries out framing, forms the PCM basic group signal of NRZ sign indicating number type;
The PCM signal transformation of NRZ sign indicating number type is become the PCM signal of HDB3 sign indicating number type.
6. PCM digroup transmission system, described PCM digroup comprises telephone path signal, frame synchronizing signal and line letter signal signal, this PCM digroup transmission system comprises HDB3/NRZ code conversion circuit and the elastic storage device that links to each other with described HDB3/NRZ code conversion circuit, the Signals ﹠ Systems clock signal synchronised of described elastic storage device output, it is characterized in that, also comprise:
Clock, frame synchronization, multi-frame synchronous extraction circuit are used for extracting clock, frame synchronization, multiframe alignment signal from the PCM signal of HDB3 sign indicating number type or from the PCM signal of the NRZ sign indicating number type of described HDB3/NRZ code conversion circuit output;
At least one and the low speed line interface that described elastic storage device links to each other, each line interface comprises
The u interface of one ISDN is used for ADPCM voice signal and signaling-information, monitoring alarm signal are delivered to telephone line together and sent, and from the low speed signal of telephone line reception from far-end;
Adpcm encoder links to each other with described elastic storage device, is used for the PCM signal pressure of NRZ sign indicating number type is shortened into the low speed signal of the identical content of ADPCM;
Output time solt is adjusted circuit, links to each other with described adpcm encoder, is used for described ADPCM low speed signal is adjusted to the signal format of described u interface requirement; The output that described output time solt is adjusted circuit is connected to described u interface;
Input time slot is adjusted circuit, links to each other with described u interface, is used for the signal of described u interface output is adjusted to the signal format that ADPCM decoder requires; With
ADPCM decoder is adjusted circuit with described input signal time slot and is linked to each other, and is used for compressed ADPCM low speed signal is decoded into the PCM signal of NRZ sign indicating number type.
The framing circuit links to each other with described a plurality of low speed line interfaces, and the PCM signal flow that is used for frame swynchronization code, multi-frame synchronous code and line signalling sign indicating number are inserted into NRZ sign indicating number type goes;
NRZ/HDB3 code conversion circuit links to each other with described framing circuit, is used to export the PCM signal flow of HDB3 sign indicating number type;
Microprocessor, link to each other respectively with above-mentioned each circuit, be used to specify the signal of the different speech channels in the different low speed line interface transmitting-receiving PCM basic group code streams, the adpcm encoder of controlling in the low speed line interface carries out transparent transmission to signaling-information in the PCM basic group code stream and monitoring alarm signal; With
System clock circuit links to each other respectively with above-mentioned each circuit, is used to the clock signal of system, synchronizing signal and the timing controling signal that provide unified.
7 PCM digroup transmission systems as claimed in claim 6 is characterized in that the compression ratio of described adpcm encoder is 1/2, and described low speed line interface has 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95111608 CN1134634A (en) | 1995-04-24 | 1995-04-24 | PCM digital basic group transmission system and its transmission method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95111608 CN1134634A (en) | 1995-04-24 | 1995-04-24 | PCM digital basic group transmission system and its transmission method |
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| CN1134634A true CN1134634A (en) | 1996-10-30 |
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| CN 95111608 Pending CN1134634A (en) | 1995-04-24 | 1995-04-24 | PCM digital basic group transmission system and its transmission method |
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1995
- 1995-04-24 CN CN 95111608 patent/CN1134634A/en active Pending
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