Method of transmitting digital streams over higher rate channels and a device for implementing same

DETAILED DESCRIPTION For this, the present invention provides a method of the above defined type, wherein: on the emission side, with a clock signal H.
sub.
i associated with the digital stream D.
sub.
i, the starting times of the packets are controlled by means of clock signal H.
sub.
i, so that the time interval separating the departure of two successive packets is equal to p times the period of the clock signal H.
sub.
i, and on the reception side, the successive arrival times of the packets are determined by recognizing the synchronization words, and the clock signal H.
sub.
i is restored by dividing each time interval separating the arrival of two successive packets by p.
The method of the invention overcomes the drawbacks of known techniques.
It consists essentially in generating information packets and transmitting these packets with a periodicity derived from the timing of the incoming signal.
Restoration of the clock timing at the reception side is derived from the periodicity of arrival of the packets.
Furthermore, if each packet is dimensioned so as to contain a whole number of bytes of information bits, it then becomes possible to transmit a byte synchronization without increasing the complexity of the device.
Such a structure is particularly adapted for making a digital channel capable of transmitting a 64 kbit/s signal by offering codirectional type accesses conforming to the recommendation G 703 of the CCITT.
Furthermore, since the digital channel is asynchronous with the timing H.
sub.
i to be transmitted, the transmission of the packets may be affected by considerable jigging.
The purpose of the invention is also to overcome these defects.
For this, and advantageously, with a clock signal H.
sub.
c associated with the digital channel: at emission, the time shift between each control time of the starting of a packet and the following transition of the clock signal H.
sub.
c is determined, the value of the shift is coded in binary form, and it is emitted by means of the binary elements of the preamble, and at reception, the binary elements coding the time shift are received, they are decoded so as to determine the value of said shift, and the phase with which the clock signal H