COMMAND RANGING & TELEMETRY UNIT CORTEX
Is.Rev.
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Page 21
1.6.1.2.
PM and FM Demodulation
Input carrier frequency
60 to 78 MHz
Spectrum analysis
Yes (spectrum analysis and IF demodulation are mutually exclusive)
IF level measurement accuracy < 2 dB
1.6.1.2.1. PM Demodulation
Carrier acquisition modes
Automatic (global FFT analysis) or Manual (sweeping)
Carrier acquisition
Select highest component, for low modulation index (< 1.3 rad.)
Spectrum correlation, for high modulation index (anti-sideband)
Acquisition & tracking range
± 10 to ± 500 kHz
PLL type and 2 Bn Loop bandwidth (CRT XL Quantum)
2nd order
10 Hz, 30 Hz, 100 Hz, 300 Hz, 1000 Hz or 3000 Hz
PLL type and 2 Bn Loop bandwidth (CRT eXplorer)
2nd and 3rd order
0.1Hz, 0.3 Hz, 1 Hz, 3 Hz, 10 Hz, 30 Hz, 100 Hz, 300 Hz, 1000 Hz,
3000 Hz
User-selectable 0.1 Hz to 3000 Hz
Acquisition threshold (CRT XL Quantum)
C/No = 20 dB.Hz (for 2Bn = 10 Hz). Measured on a pure carrier
Acquisition threshold (CRT eXplorer)
C/No = 8 dB.Hz (for 2Bn = 1 Hz). Measured on a pure carrier
Tracking threshold
≤ acquisition threshold
Maximum Doppler rate
≤ 50 kHz/s and C/N0 > 50 dB.Hz (for 2 Bn = 1,000 Hz)
≤ 100 kHz/s and C/N0 > 60 dB.Hz (for 2 Bn = 3,000 Hz)
Output video bandwidth
DC to 2 MHz
Doppler measurement
IF offsets and cumulated phase variations (Integrated Doppler)
Diversity combining
Optional. Post-combination. Up to 3-dB gain with equal-strength signals
1.6.1.2.2. FM Demodulation
Pre-detection filter bandwidth
10, 5, 3, 1.5, 1 MHz, 500, 300, 150, 100, 50, 30, 15, 10 and 5 kHz
(single-side at 1 dB)
PCM/FM BER degradation
2 dB typical at Eb/No = 7 dB, with the matched pre-detection filter
AFC time constant
1, 10, 100 or 1000 ms
Discriminator number of periods 1 to 16
Output video bandwidth
Depends on the Pre-Detection filter and Discriminator programming
