3.3
Demodulation
3.3.1
IF Processing
Signal Processing:
IF signal selection (Nominal or Alternate input).
Automatic gain control: the signal level must be in the range –10 dBm to –50 dBm.
Analog-to-Digital conversion of the received signal.
IF acquisition: the programmed acquisition range must be compatible with the maximum
frequency uncertainty (Doppler shift, oscillators drift,...).
Cable equalizer filter (see Section 3.7 ): cable loss equalizer with programmable attenuation.
IF filtering: matched filter, adjacent canal rejection or custom FIR filters (option).
Test & Monitoring:
A number of status enable to monitor the demodulation process at IF: IF signal level, PLL
status, carrier offset, etc...
Spectrum analysis: allow to visualize the received signal spectrum.
Vector analysis: check that the displayed constellation is correct and corresponds to the noise
and signal characteristics.
Filter analysis: display in real time the pulse and frequency responses of the digital filtering.
3.3.2
Bit Synchronization
3.3.2.1
Signal Processing
Matched filters: basic supply: Integral & Dump. Optional: Root Raised, Raised filters with
programmable roll-off factor, GMSK, user-programmable FIR filters (see next section).
Symbol phase recovery
Test & Monitoring: a number of status enable to monitor the bit synchronization process: PLL status,
signal to noise ratio (Eb/No), etc...
© Safran Data Systems – IMP000074 e14r1
HIGH DATA RATE RECEIVER
HDR-4G+ USER'S MANUAL
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Ref.
DTU 100782
Is.Rev
3.5
Date:
June 1, 2021
Safran Data Systems
.
Page 78