Reference Frequency; External Reference; Internal Reference; Multi-Symbol Pcm/Fm Demodulator - Parameters Recommended Setting - Safran CORTEX CRT Quantum User Manual

3.3.1.3.4. Multi-Symbol PCM/FM Demodulator – Parameters recommended setting

Introduction

3.3.1.3.4.1.
Several parameters are available for configuring the MS/FM demodulator. These parameters are described in the
STI 100013_TTC document (refer to "IF receiver Extension" table). Recommendations to set these parameters
are given below.

Modulation index

3.3.1.3.4.2.
Using the legacy FM demodulation (when MS-FM is turned off), the demodulator is able to withstand a non-
accurate modulation index. However, with MS-FM demodulation, inaccuracies of modulation index are a critical
point for the receiver performances. The MS/FM receiver must take into account the actual value of the FM
modulation index to work properly and keep the benefits of MS/FM demodulation.

Nominal mode
In this mode, the MS-FM demodulator uses the theoretical value 0.7. This mode is suitable for numerically
modulated PCM/FM signal. For analog FM modulator, this mode is not recommended.

Manual mode
Selecting this mode, the user can define the modulation index in the Index Value field. This mode is only
recommended for digital modulator with a known modulation index.

Automatic Mode
Selecting this mode, the demodulator analyses the received signal and estimates the modulation index.
This mode is recommended when using an analog modulator.
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COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
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Safran Data Systems
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Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
Page 34