Installation guide

Troubleshooting
Block Descriptions for Option 501, 502, 503, 504
1-121
A17 Synthesizer. The VCO is capable of being tuned from 500 MHz to 1000 MHz.
The tuning of the VCO begins with a 10 MHz signal from the A18 Reference. The 10 MHz reference is divided
down to 5 MHz to reduce fractional spurs in the phase detector. The 5 MHz reference is then phase compared
to a divided down VCO output. The primary division of the VCO is performed within the Tesera pre scaler
ASIC; the pre scaler divisor is provided by the Paren ASIC. The output of the phase detector is integrated and
then used to tune the VCO.
Depending on the desired output frequency, the VCO is either divided by two, multiplied by two or four, or left
unchanged. The final signal is filtered and routed to the A13 Output.
The baseband FM and PM from the A18 Reference are added to the VCO on the A17 Synthesizer. Depending
on the modulation rate, there are two different paths for the modulation to be added to the VCO. If the rate is
outside the VCO PLL bandwidth, the baseband signal is scaled and applied to the VCO. If the baseband rate
is within the VCO PLL bandwidth, the baseband signal is scaled and sent to the Sigma-Delta Modulator for
digitizing. The digitized signal is used by Paren and Tesera to change the VCO tuning and implement FM.