A2537-002/01 February 2020 6-1 SEMCO Proprietary Information
SECTION 6 - DEMODULATOR AND EMBEDDED BIT SYNCHRONIZER OPERATION
6.1 Overview
The three RC100C-2 Demodulators and embedded Bit Synchronizers are FPGA-based designs that
function independently. These demodulators and embedded bit synchronizers are designed to support all
modulation formats and emerging technologies used at both U.S. and international flight test ranges.
The Demodulator and embedded Bit Synchronizer controls and features include basic and Advanced
Settings. Table 6-1 lists selectable Demodulator/Bit Synchronizer controls, settings and features.
Table 6-1
Demodulator Modes and Features
Standard: PCM/FM, NTSC Video, PM, BPSK, A/U/S/O/QPSK Tier 0 Trellis FM, Tier I SOQPSK-TG, Tier II and Multi-h CPM
Optional: PM, PM/PSK Sub-carrier, FM/FM Sub-carrier, GMSK, UQPSK/SQPN Spread Spectrum and Coherent AM;
FIR filters AUTO-SET feature as a function of data rate input (IFBWs and Baseband Video BWs)
15 selectable IF FIR filters and Baseband FIR filters calculated and presented to the user as a function of data rate
Embedded Bit Synchronizer and De-Randomizer
2 Analog, 1 Digital Clock and 1 Digital Data Output per channel
Video Low Pass Filtering, Video Polarity and De-Emphasis
AUTO loop bandwidth and acquisition sweep settings optimized for demodulator format and data rate
User-selectable loop bandwidths, acquisition sweep range and sweep rates with AUTO feature disabled
Trellis FM Modulation Index Selection
“Fast Acquire” for fastest acquisition time (Tier 0, I and II), with “Track Loop Bandwidth” for PM/PSK and SOQPSK-TG
FM Low Data (Sweep) Rate (<10 kbps) feature
Data Quality Metrics (DQM) and Data Quality Encapsulation (DQE)
SOQPSK Low Density Parity Check (SOQPSK-LDPC)
SOQPSK Space Time Coding (SOQPSK-STC)
Viterbi and Turbo Forward Error Correction Option
These features are accessible from both the front panel displays and keypad and the remote (network)
GUI as described in subsequent paragraphs of this section.
6.2 Demodulation Mode Selection
Demodulation Mode selection using the front panel displays and keypad is shown in Figure 6-1. The
operator pushes the DEMOD MODE button to access the Demod Menu display, uses the UP (2) and
DOWN (8) arrows to scroll to Mode in blue, and then pushes ENTER or SELECT (5) to highlight the Mode
selection window in bright magenta. Using the UP (2) and DOWN (8) arrows, the operator selects the
desired <Ch1> Demodulation Mode and then pushes ENTER or SELECT (5).
Using the horizontal LEFT (4) and RIGHT (6) arrows, the operator selects <Ch2> in the Demod Menu
header display bar. The operator then pushes ENTER or SELECT (5) to highlight the Mode selection
window in bright magenta. Using the UP (2) and DOWN (8) arrows, the operator selects the desired
<Ch2> Demodulation Mode and then pushes ENTER or SELECT (5). Using the horizontal LEFT (4) and
RIGHT (6) arrows again, the operator selects <Comb> in the Demod Menu header display bar and repeats
the process for selecting the Combiner demodulation mode.
Note:
All 3 demodulator channels will change to the selected demodulator mode if
Diversity Slaving has been enabled (see SECTION 2, paragraph 2.6.1.2, which
describes and illustrates how to enable the
Diversity Slaving feature).
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