Test Modulation; Data Generation; Data Sources; Pseudo Random Data - Safran CORTEX Series User Manual

3.6

Test modulation

The test modulator allows to test the carrier acquisition, demodulation and decoding processes:
Functional tests: Telemetry reception and processing without noise (IF demodulation, bit
-
synchronization, BER measurement)
BER tests: BER measurement in the presence of noise. Bit-by-bit comparison of the simulated
-
PCM to the regenerated PCM from the bit synchronizer (File mode or pseudo random mode).
3.6.1

Data Generation

The Test Modulator allows generation of test data with the following scheme:
3.6.1.1

Data Sources

The Test Modulator allows to generate (or encapsulate) test data from the following sources.
Four data sources are available:

Pseudo-random binary sequences (PRBS for BER testing), of order 7, 10, 11, 15, 23 and 31,

Data from hexadecimal-coded files on the hard disk (up to 32768 bytes)

External data (typically PCM + clock).

Playback of high size binary files from attached storage (either internal or external)
3.6.1.1.1

Pseudo Random Data

Six PRN generators (Pseudo Random Noise) providing pseudo-random bit sequences of
programmable length and period can be selected for BER analysis. Data sequences are sequences of
maximum length which are generated by means of feedback shift registers.
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Data input
Optional
Input Format
Data output
Optional
over LVDS, ECL,
Playback
Wizard-Link...
Data
Data Generating Unit
Ext.
Optional
Data
External
Generation
Framing
PRBS, File,
Playback,
ASM insertion,
External
Scrambling

Figure 53: Data Generation Scheme

Ref.
Is.Rev
Date:
Optional
Internal
Framing
RS,LDPC enc.
ASM insertion,
Scrambling
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DTU 100782
3.5
June 1, 2021
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Modulating
Unit
.
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