Demodulator (Figure 6-6) - Comtech EF Data SDM-309B Installation And Operation Manual

SDM-309B Satellite Modem

6.1.4.2 Demodulator (Figure 6-6)

TP10
TP23
TPG
TP1
TP2
TP3
TP4
TP5
TP6
TP7
TP8
MN/U-SDM309B Rev. #
VCXO Control Voltage
Approximately 0 to +2.5V sweep range.
Discriminator Voltage.
Nominally +2.5V with 6 dB noise at 128 Kbs.
Ground test point
Q EYE pattern.
Level is 1V P-P at the center of the eye crossing. The DC offset is about +2.4V.
Q THRS - Q channel threshold voltage. +2.9V DC.
I THRS - I channel threshold voltage. +2.9V DC.
I EYE pattern.
Level is 1V P-P at the center of the eye crossing. The DC offset is about +2.4V.
Q CLK THRS +
Q channel + clock threshold. +2 to +3V DC.
Q CLK THRS -
Q channel - clock threshold. +2 to +3V DC.
I CLK THRS - I channel + clock threshold. +2 to +3V DC.
I CLK THRS +I channel - clock thr
eshold. +2 to +3V DC.
Figure 6-6
Maintenance
6-6–9