COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
This document is the property of Safran Data Systems.
It cannot be duplicated or distributed without expressed written consent.
3.6.4.5. Tone Level Ratio
For the ESA, ESA-like and USB standards, the minor tones being superposed to the major tone, it is necessary
to program the level ratio between the two tones:
Let's call
the absolute Major tone modulation index for ambiguity resolution,
the absolute
Minor tone modulation index and
the absolute Major tone modulation index for measurements phase.
The IFM ranging modulation index (let's call it Idx), offset 6 in IFM table, has to be configured with:
The Major/Total amplitude ratio for ambiguity resolution has to be configured with the value of
.
In this case
and
.
The Major/Total amplitude ratio for measurements has to be configured with the value of
in the
range [0.01 - 1.0]. Value 0 is used for compatibility with previous software (equivalent to value 1)
This parameter is not significant for the INMARSAT, LMCO and ESA code standards.
3.6.4.6. PLL Bandwidth
The PLL loop bandwidth is programmable from 0.1 Hz to 8 Hz (Cortex CRT Quantum), and from 0.001 Hz to 8
Hz (CRT eXplorer). See Section 3.6.12 for detailed performances in the presence of noise and Doppler. For the
INMARSAT and LMCO standards, the loop bandwidth must be set between 1 Hz and 8 Hz. Lower values are not
compatible with the tone set times. For other standards, see also next section.
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