3
rd
Generation Compact RDMS
TM
Telemetry Receiver
28
Quasonix, Inc.
O - Off
H - Hold
T - Track
A - Acquire
H <t> - Sets AFC hold below Eb/N0 <t>, -20.000 to 30.000 dB or -100.000 is off
C A - Sets AFC coefficient to be automatically set based on bit rate
C <c> - Sets AFC coefficient to <c>, 0.0003511 to 46.018 seconds
L <m> - Sets AFC correction limit to <m>, 0.000006 to 46.666661 MHz
T L <t> - Sets AFC power detect low threshold to <m>, 0.000000 to 0.999985
T H <t> - Sets AFC power detect high threshold to <m>, 1.000015 to 65536.000000
O <e> - Sets AFC data path override enable to <e>
where: <e> - enable
0 - Disabled
1 - Enabled
AD <d> - Sets Acquire mode minimum delta offset coefficient to <d>, 0.000 to 5.000
AS <s> - Sets Acquire mode settling time to <s>, 10 to 10000 ms with a 5 ms resolution
SYS <d> - Sets the AFC status tracking display mode to <d>
where: <d> - display mode
D - Detected
C - Compensated
The Sys d setting is used to change whether detected or compensated offset is displayed in the SYS output
Note these display values are only different in Acquire mode.
When AFC mode is set to Acquire, the RDMS goes to the 'armed' state. In the armed state, the AFC tracks and
compensates any detected offset regardless of the signal Eb/N0. (In Tracking mode, if the Eb/N0 hold is enabled, the
tracking and compensation stop if the signal Eb/N0 is below the hold threshold.) In this case, the detected and
compensated offset are the same.
The detected offset is averaged over the specified settling time (AFC AS <s>) and then the delta to the last average
is determined. If the delta is less than or equal to the minimum delta (AFC AD <d>), the AFC moves to the
'triggered' state, the compensated offset remains at the point where it was when triggered, and the Eb/N0 and
detected AFC duty cycle where the trigger occurred are saved. In the triggered state, the AFC still detects the offset
but the compensated offset remains fixed at the point where the AFC triggered. In this case, the detected and
compensated offset will likely be different. The detected offset continues the averaging and delta comparison and if
either the delta comparison or the absolute offset relative to the current trigger point exceeds the minimum delta
AND the Eb/N0 is greater than or equal to the Eb/No where the last trigger occurred, the AFC will 'retrigger' and
move the compensated offset to the current, new, offset.