Motorola MTR2000 Manual page 55

EXCITER MODULE
MODEL TTD6301C
68P81094E12-D
Schematics (Sheet 4 of 14)
12/26/01
Signal
Description/Nominal Signal Levels
Path
Bandshift signal from synthesizer (U3402-pin 7, AUX 1) controls series pass transistor Q3201 and
A
Q3202 to provide supply voltage to high VCO (upper half of band) or low VCO (lower half of band).
Bandshift signal Hi Low range VCO selected (132-153 MHz)
Bandshift signal Lo High range VCO selected (153-174 MHz)
+8.7 V supply; +10 V filtered by Supply Voltage Filtering Q3200,C3201,C3240, C3241 and R3201
B
Enabled VCO (selected by VCO select circuitry) generates RF output frequency determined by the
C
DC control voltage at steering line.
VCO_OUT; Output power between +3 dBm and +9 dBm
D
The frequency of the VCO's are tuned with CR3201, CR3202 and CR3213 for the low range and
E
CR3208, CR3209 and CR3212 for the high range.
If the synthesizer is not locked, steering line voltage will be either less than +2.5 V or higher than
+11V.
Low range VCO enabled
Steering line voltage +4V approx. 132 Mhz
Steering line voltage +9V approx. 153 Mhz
High range VCO enabled
Steering line voltage +4V approx. 153 Mhz
Steering line voltage +9V approx. 174 Mhz
VCO modulation signal from U3401-1
F
BLOCBLOCK DIAGRAM