User's Manual

5.8GHz PDH User’s Manual
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2.3.2 System Principle
N number of E1 signals, digital service, 9600b/s system net control and 9600b/s
computer data communication etc. multiplexed in a multiplexer to a specific microwave
frame code. After QPSK modulation, the system sends the transmission to the ODU
through only one IF cable. It enter the ODU upstream IF signal communication through
equalized electric circuit interface, higher frequency converter, power amplifier, filter,
duplexer and are then transmitted out through the antenna system.
After the opposite terminal’s antenna system receives the microwave signals, it is passed
on to the duplexer, LNA, low frequency converter, filter, dual frequency converter and
then to the IDU. In the IDU, it passes through the QPSK demodulator to recover the
microwave frame signal. This frame signal is then processed through de-multiplexer to
recover the N number of E1 signal and other service signal.
The monitor unit in the equipment is controlled by the CPU (central processing unit) to
function as: monitoring, controlling, dispatching, alarming, processing and indicating
signals etc. Based on the statistical result of BER test in de/multiplexer, we have
1E-3BER, 1E-6BER and frame loss signals.
Digital service adopts the Analog rule of 64kbps and PCM (Pulse Code Modulation)
decoder method to service communication, complete address selection and full address
function. Through simulation transmitting and receiving, to complete the multiple
categorized public affairs connection. The dialing mode adopts DTMF system.
System network management uses PC machine of above PII operating system.
Under WINDOW environment’s SNMP network management software, it is possible to
hold communication through the same equipment, collect all the equipment’s status in the
network and select records for printing. The introduction of animation design makes the
network topology and equipment selection status crystal clear.