Construction of a frame

E2 frame forms by multiplexing of 4 El digital streams and its duration is equal to 125 us. Frame, which consists of service and information bits is divided into 4 parts (groups) for increasing of noise immunity of the justification commands (JC).

Every, group has a 8 service and 256 information bits. First 8 service bits of the first group contain a codeword 11100110 of frame alignment signal (FAS).

Symbols of the justification command (SJC) are transmitted by the redundant code and placed in the group 2-4 (bits 1-4). First 4 bits of group 4 contain a negative justification symbols (NJS).

Figure 6.1 -

SJC N - symbol number N of the justification command;

DD - discrete data;

SC - voice service communication (using 32 kbit/s Adaptive Delta Modulation);

Forming of the PCM frame. Representation of frame in the matrix form is more convenient. Bits 9-12 of group 4 transmit symbols of positive justification (SPJ).

Figure 6.2 – Secondary order frame with positive/zero/negative justification

Let’s consider my variant:

bits;

bits.

The service command:

bits.

The discrete information:

bit;

bits;

bits;

bits;

bits.

bits.

bit;

For my variant bit.

Дата добавления: 2015-08-18