Comtech EF Data SDM-100A - Manual (Page 149)

SDM-100A Satellite Modem Maintenance
Rev. 0 5–7
5.1.4.2 Modulator Test Points
TP 1 DATA CLOCK TTL level clock that is locked to the incoming data to the
interface card.
TP 2 SYMBOL CLOCK TTL level clock that is locked to the incoming clock at the
interface card. This clock is running at the symbol frequency
and not at the data rate.
The frequency is equal to:
BPSK = 2X Bit Clock
QPSK1/2 = Bit Clock
QPSK3/4 = 2/3 X Bit Clock
QPSK7/8 = 4/7 X Bit Clock
TP 4 Q DIGITAL FILTER Analog output from the digital filter.
TP 5 I DIGITAL FILTER Analog output from the digital filter.
TP 3 Q MIXER Analog output of the Q channel baseband reconstruction
filter and the input to the RF modulator.
TP 6 I MIXER Analog output of the I channel baseband reconstruction
filter and the input to the RF modulator.