Comtech EF Data SDM-650B - Manual (Page 153)

SDM-650B Satellite Modem Maintenance
Rev. 6 6–9
6.1.3.2 Demodulator
Refer to Figure 6-8.
TP10 VCXO Control Voltage.
Approximately 0 to +2.5V sweep range.
TP23 Discriminator Voltage.
Nominally +2.5V with 6 dB noise at 128 kbit/s.
TPG1 Ground.
TP1
Q EYE Pattern.
Level is 1 Vp-p at the center of the eye crossing. The DC offset is about +2.4V.
TP2 Q THRS — Q channel threshold voltage, +2.9 VDC.
TP3 I THRS — I channel threshold voltage, +2.9 VDC.
TP4 I EYE Pattern.
Level is 1 Vp-p at the center of the eye crossing. The DC offset is about +2.4V.
TP5 Q CLK THRS +.
Q channel + clock threshold, +2 to +3 VDC.
TP6 Q CLK THRS -.
Q channel - clock threshold, +2 to +3 VDC.
TP7 I CLK THRS -.
I channel + clock threshold, +2 to +3 VDC.
TP8 I CLK THRS +.
I channel — clock threshold. +2 to +3 VDC.
Figure 6-8. Demodulator Test Points