DE3442883A1 - Integrated-services system for digital transmission of broadband and narrowband signals - Google Patents

Abstract

The invention relates to a system for digital transmission of broadband signals, for example video or videophone signals, and narrowband signals, for example audio and telephony signals, at the bit rate of a PCM-quaternary system of 139.264 Mbit/s according to CCITT G703.9 in a time-division multiplex frame and is characterised in that the frame comprises 8 lines for every 366 bits, giving a total of 2928 bits, that an additional 8-frame multiframe is defined and that the multiframe is characterised by means of one bit per frame. <IMAGE>

Description

Integrated service system for digital transmission

of broadband and narrowband signals The invention relates to an integrated System for the digital transmission of broadband and narrowband signals according to the generic term of claim 1.

Such systems are known, for example one is in the German Offenlegungsschrift 32 30 943 has been proposed.

This system is a multiplex frame with 10-bit time slots has been proposed that the advantage of a speed reduction to the Has a factor of 10 compared to a one-bit time slot. However, the disadvantage is very large storage space requirement.

The present invention had the object of providing a system of Specify initially mentioned type, which has a frame structure, which only a little Requires storage space.

In particular, the effort for elastic storage should be for each Service below about 20 bits.

This task is solved by the characteristic features of claim 1.

The advantage of the system according to the invention is that its frame structure Requires little storage space, especially the one for each service required elastic memory has a capacity of less than about 20 bits.

Further advantages result from the configurations according to FIG Subclaims.

The invention will now be described with reference to the figures.

Figure 1 shows the structure of the multiplex frame.

FIG. 2 shows the content of a three-bit combination of the fifth Frame line for the various frames in the form of a Table again.

In Figure 1, the multiplex frame is an embodiment for the system according to the invention in matrix form dartgentelltl There are the eight lines A, B, C, D, E, F, G, H and the individual bit positions in columns 1 to 12, 13. . .20 z . .366 recognizable. The first line A of such a frame contains in the first twelve bit positions A1 to A12 the frame identifier 111110100000. In the following Bit positions 13 to 16 are provided with special bits Y1 to Y4, which are used for identification the superframe (e.g. with Y1) or to identify the individual frame with a number (e.g. using bits Y2 to Y4). One renounces the use of the special bits Y1 to Y4, for example by adding the identifier of the superframe through the signaling bit El and the identification of the drops individual frames by number, this results in further simplifications; by shifting the F bits F1 to F2484 by 4 positions forward and inserting them the special bits Y1 to Y4 in line H in positions 9 to 12 result, for example then a shortening of the elastic memory for the composite signal to 12 bits. on the first bit position of the other lines B to H are the stuffing identifiers SK3, SK4, Sk5 in lines B, C, D, the signaling Sig in line E and one bit for the fax simile service Fac in line F and the first two stops Transfer SK1 and SK2 in line G and H, respectively.

The next bit positions 2 to 4 of lines B to H are through Sound information T1 to T21 filled up. A PCM signal is also shown in the lines B to H are transmitted in bit positions 5 to 11, with the bit positions 9, 10 and 11 of line E provide information that differs from frame number to frame number wear, which is recorded in Figure 2 in the form of a table.

The bit positions 9 to 11 of the last line H and all not mentioned Bit positions of all eight lines are indicated by the information bits F1 to F2838 of the FBAS signal busy.

The superframe according to the proposed system now consists of eight Frame with the structure according to FIG. 1. The identifier for the superframe takes place as already indicated above, with the help of a special bit Y1 or with the signaling bit El, for example, by transmitting an identifier 10000000. In each of the eight The frame is in the area X X X, that is, the bit positions 9 to 11 of line E. Transmit signal that contains certain fixed bits and each stuffed bit.

The stuffing identifier for the stuffed bits is previously determined by the stuffing identifier SK1 to SK 5 transferred and evaluated by majority decision.

In FIG. 2, the content of the three bits X X X is dependent in a table the frame number shown. There is a sound signal bit in every second frame T and two video signal bits F are transmitted. In frames 2 and 4 there are three signaling bits Sig or three Faximilesignalbits Fac transmitted while in frames 6 and 8 respectively a tone signal bit T and a PCM signal bit P are transmitted with two free bits each will. The bits marked with an underscore are the stuffing bits.

Some more general information now follows.

The frame length is determined from eight lines of 366 bits each, equal to 2,928.

The frame rate is calculated as 139.264 MHz divided by 2.92.8 equal to 47.5628 SHz. It is repeated after eight frames, i.e. after a full superframe. The transmission rates for the individual services as well as their relative deviations are the following values.

FBAS signal F1 to F2838 results in 134.9833 Mbit / s, which corresponds to one relative deviation of -1.2. 10 4.

There are also eight stuffing bits in eight frames, which is the rate of 135.0309 Mbit / s or the relative deviation of +2.3. 10 4 results.

The tone bits T1 to T21 and four tone signal bits result in eight frames a transmission rate of 1.0226 Mbit / s, to which the relative deviation of -5.2. 10 3 corresponds.

In addition there is a darning signal bit in eight frames, what a Total bit rate of 1.0285 Mbit / s (+4.8 10Lt) results.

For the PCM signal, bits P1 to Plot3 result in 2.045 Mbit / s (-1.5 10 3).

In addition, there is a stuff bit in eight frames, which gives a total bit rate of 2.051 Mbit / s (+1.5 10 3) results.

For signaling Sig, 2 bits in eight frames result in 59.45 kbits / s (-7.1. 10 There is also a stuffing bit in eight frames, which gives a total of 65.40 kbits / s (+2.1 . 10-2) results.

The values for the faximile signal are the same as for the Signaling.

If the superframe identification in the signaling bit El is a If the frame is transmitted, an effective value still remains for the signaling of 41.6 kbit / s if the four initially unused bits O in frame 6 and Frame 8 used for signaling transmission.

The cost of elastic storage for the respective services is as follows: for the video signal 20 bits, for the sound signal, signaling and Faximile 8 bits each and 16 bits for the PCM signal, although because of the influence A safety reserve of 4 bits each was factored in due to jitter. If, as described above, the marking of the overframe in the Signalisieruhg leads and omits the numbering of the individual frames, so that overall If the special bits Y1 to Y4 can be dispensed with, the structure of the multiplexer can be further simplified, and for the video signal there is then an elastic store of only 12 + 4 equal to 16 bit length required.

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Claims (10)

Claims ()) System for the digital transmission of B-sideband signals, for example video or picture telephone (BiFe) signals, and narrowband signals, e.g. audio and telephone signals at the bit rate of a PCM quaternary system of 139.254 Mbit / s according to CCITT G703.9 in a time multiplex frame, characterized in that, that the frame consists of 8 lines of 366 bits each equal to 2,928 bits, that an additional Superframing is defined by 8 frames and that the superframing is defined by means of one bit is marked per frame (10000000). 2. System according to claim 1, characterized in that in a first Line (A) of the frame the frame identifier (A1.. .A12) is transmitted. 3. System according to claim 2, characterized. it is known that in each case the same bit position (column 1) in 5 lines (B, C, D, G, H) of a frame Bit for stuffing identification (SK3, 4, 5, 1, 2), one bit in a sixth line (E) for Signaling (Sig) and in a seventh line tF) a bit for Faximile (Fac) is transmitted will. 4. System according to claim 2 or 3, characterized in that each the bits in three identical bit positions (columns 2 to 4) in seven rows (B to H) for tone (T1 to T21). 5. System according to one of claims 2 to 4, characterized in that that in four identical bit positions (columns 5 to 8) in seven lines (B. . . .H) and in three other identical bit positions (columns 9 to 11) in five lines (B to D and F, G) Transfer bits for a PCM telephony connection (P1 to P43) will. 6. System according to claim 5, characterized in that on the three further bit positions in a seventh line (E) of a frame are determined Bits and stuffed bits are transmitted. 7. System according to claim 2, 3, 4, 5 and 6, characterized in that that on all the not mentioned bit positions of the lines of a frame Bits (F1 to F2838) for the composite video signal are transmitted. 8. System according to claim 3, 4 and 6, characterized in that, depending on the frame number, the three further bit positions in the seventh line (E) are occupied as follows: Frame number XXX 1 TFF - 2 Sig Sig sig 3 T, F 4 Fac Fac Fac 5 TFF 6 0 OT 7 T 8 0 OP where for the transmission of tone T, of FBAS signal F, of signaling Sig, of Faximile Fac, for PCM telephony P and 0 stands for unoccupied and where that bit is marked by an underscore that was determined by majority decision on the last stuffing identifier bits ( SK1 to SK5) has been stuffed. 9. System according to one of the preceding claims, characterized in that that the bit characterizing the superframe is provided for signaling (Sig) Position (El) or as one of the special bits (? I to y4). 10. System according to one of the preceding claims, characterized in that that the identification of the individual frames by means of a number (1 to 8) three or four special bits (Y2'to Y4) occur.