Tiernan TDR60, Инструкция по установке и эксплуатации

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QPSK Demodulator Application Notes
01-0868-401B 12/02 63
Diagnostic Commands
This section presents demodulator troubleshooting commands.
QD G3
Use this command to display the decoder registers. The register values are all in
hexadecimal.
The registers that are most helpful for troubleshooting are described in this
section.
Register 8 (Power Level) This register should be almost equal to A0. This indicates
that the AGC loop is locked and the signal level is optimum at the analog to digital
converter inputs.
Reed-Solomon Corrected
This register displays the total number of byte errors
corrected by the Reed-Solomon decoder. It is reset to zero upon reaching max
count.
Any substantial channel noise will cause this register to be greater than zero.
Reed-Solomon Uncorrected
This register displays the total number of byte errors
that were detected, but not corrected, by the Reed-Solomon decoder. It is reset to
zero upon reaching maximum count. For normal operation this register must be
zero.
Any non-corrected byte errors will result in some form of degradation in the
decoder.
Viterbi Bit Error
This register displays the number of channel bit errors during the
last measurement period. This register is used to estimate E
b
/N
0
. If this register is
zero, the E
b
/N
0
is 16.00 (no noise).
Any channel noise will cause this register to be greater than zero.
QD OFFSET
Use this command to confirm the location of the carrier. The definition of this
query is:
OFFSET = Actual RF - Programmed RF
The units are in Hz.