A2537-002/01 February 2020
3-2
SEMCO Proprietary Information
3.1.1 Single Card Receiver (SCR) Hardware
The RC100C-2 employs 2 Single Card Receiver (SCR) Circuit Card Assemblies (CCAs) that provide for
independent RF channel tuning across 200-1150 MHz, 1415-1585 MHz, 1710-1850 MHz, 2185-2485 MHz
and 4400-5250 MHz, as well as providing for an independent AM detector, AGC and AFC circuitry and a
filtered, linear 70 MHz IF output that is then distributed as required throughout the receiver.
The SCR also provides for a CH1 and CH2 70 MHz IF input. These inputs are used for a fixed 70 MHz
RF input that bypasses the 1
st
and 2
nd
Local Oscillator stages, as well as used for recorded pre-d 70 MHz
playback.
The SCR also provides 28 selectable SAW IF filters (14 IFBW values) from 300 kHz to 40 MHz. Doubling
the number of SAW filters per IFBW selection provides for over 80 dB IF Rejection. 15 selectable IF FIR
filters are also calculated as a function of data rate and demodulator format and presented to the user.
This feature provides for a virtually unlimited number of IF filter value selections for optimum IF bandpass
filtering. An AUTO feature is also provided for both IF SAW and FIR filter selection based on data rate and
demodulator format.
Additional features include: user-selectable AM gain, low pass filtering and output impedance; dual
scalable AGC outputs and selectable output impedance; AGC Manual, Freeze and Zero; user-selectable
AFC loop speeds, including a Manual and Reference (Coherent) mode; user-selectable Frequency Offset;
Absolute, Relative and Antenna Signal Strength displays and AGC voltage displays.
3.1.2 Diversity Combiner Hardware
The Diversity Combiner is a pre-d/post-d optimal ratio combiner that processes the modulated CH1 and
CH2 70 MHz, AGC and AM and provides up to 3.0 dB C/N improvement at equal input signal levels.
Combiner features include:
A. Routing of CH1, CH2 or Combined Signal thru the Combiner CH;
B. a Best Source Select Mode and CH1/CH2 Zero Balance feature; and
C. an AGC Zero feature and Combined AGC voltage display.
3.1.3 IF Demodulator Hardware
The 3 IF Demodulators provide for 15 selectable IF FIR filters calculated as a function of data rate, and a
70 MHz digital demodulator and embedded bit synchronizer that processes the filtered 70 MHz. A de-
randomizer feature provides the user with the ability to de-randomize the input signal and output NRZ-L.
15 selectable Baseband Video FIR filters calculated as a function of data rate are also provided. An AUTO
feature provides IF and baseband FIR filter values based on data rate and demodulator format.
There are four baseband video outputs per installed demodulator that are routed to the rear panel and
available via BNC connectors:
A. Video 0 - 0-4 VDC Analog Baseband Video Output; 75 Ohm impedance
B. Video 1 - 0-4 VDC Analog Baseband Video Output; 75 Ohm impedance
C. Video 2 - Digital TTL Clock Output; 75 Ohm Impedance
D. Video 3 - Digital TTL Data Output; 75 Ohm Impedance
The IF Demodulator also provides for eye pattern, constellation and spectral sweep displays, as well as
an optional Multi-Channel programmable Bit Synchronizer, Frame Synchronizer, Bit Error Rate Tester
(BERT) and PN Pattern Generator as described in the following paragraph.
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