64 K Digital Service Channel Transmission; Service Channel Transmission Of G.703 Codirectional; Service Channel Transmission Of V.11 - NEC PASOLINK Training Course

ROI-S04488

2.11 64 K Digital Service Channel Transmission

2.11.1 Service Channel Transmission of G.703 Codirectional

2.11.2 Service Channel Transmission of V.11

Two types of transmission are provided for the service channel:
codirectional transmission conforming to ITU-T G.703 and transmission
conforming to V.11. Each transmission scheme corresponds to the type of
64K INTFC section.
(a) TX Side
A 64 kbps bipolar signal is applied to the 64K INTFC section, then
converted to a unipolar signal by the B-U CONV circuit. The
unipolar signal is then code-converted with a decoder. The code-
converted signal is stuff-synchronized with 80 kHz (approx.)
clock, then converted into a radio transmission format. After
conversion, a 80 kbps (approx.) data signal is fed to the MAIN
BOARD.
(b) RX Side
The process of RX side is the reverse of the process of the TX side.
A 80 kbps (approx.) data signal and the 80 kHz (approx.) clock
signal from the MAIN BOARD are entered in the synchronizer
circuit for the frame synchronization. The frame synchronized data
signal is de-stuffed and converted into 64 kbps data signal. The
resulting 64 kbps data signal is code-converted into G.703 signal
with an encoder circuit, then converted again with the unipolar-
bipolar converter (U-B CONV) circuit into a 64 kbps bipolar data
signal which is transmitted to the output terminal.
(a) TX Side
The 64 kbps (approx.) unipolar data signal and the 64 kHz
(approx.) clock signal are entered into 64K INTFC section. The 64
kbps unipolar data signal undergoes stuff-synchronization with the
80 kHz (approx.) clock signal, then is converted into a format for
the radio transmission and fed to the MAIN BOARD as a 80 kbps
(approx.) data signal.
(b) RX Side
The process of RX side is the reverse of the process of the TX side.
The 80 kbps (approx.) unipolar data signal from the MAIN
BOARD and the 80 kHz (approx.) clock signal are entered into
64K INTFC section. The data signal then is frame synchronized
with the frame synchronizer circuit, then de-stuffed converted into
a 64 kbps unipolar data signal with a 64 kHz clock signal, and is
fed to the output terminal.
FUNCTIONAL OPERATION
2-25