Operating instructions

TECHNICAL DESCRIPTION
4-17
Systems mode
The systems mode of the Service Monitor allows it to test communications equipment which is
designed for operation on dedicated systems such as cellular mobile radio telephone systems and
trunking radio telephone systems. Automatic testing is performed using various test programs.
These can be made to check all functions of the system, the signaling only or any intermediate
choice of functions, depending on the user's requirements.
The data processing needed to carry out these tests is handled by a 68000 microprocessor and
three Digital Signal Processors (DSPs) on the cellular radio systems board (B3 or B3/1).
The board has 1 M byte of EPROM which contains the cellular systems software and the built-in
test sequences.
The user defined sequences and user set-ups are held in 256 k byte of NOVRAM.
One of the DSPs generates the signals required to simulate the system signals, the other two
handle the signals received from the mobile.
A gate array is used for communication between the 68000 microprocessor and the DSPs.
Interfacing between the digital circuits on the cellular radio systems board (B3 or B3/1) and the
analogue circuits of the Service Monitor is handled by a dual 18-bit digital to analogue converter
for the Service Monitor to mobile signals and by a 12-bit analogue to digital converter for signals
from the mobile.