HP 8753E Service Manual

7. A synthesized subsweep is generated by A13/A14. The A3 source tracks
the synthesizer. When the source is phase locked to the synthesizer at the
start frequency, the synthesizer starts to sweep. The phase locked loop forces
the source to track the synthesizer, maintaining a constant 1 MHz 1st IF
signal.
The full high band sweep is generated in a series of subsweeps, by phase
locking the A3 source signal to harmonic multiples of the fractional-N VCO.
The 16 to 31 MHz subsweep is produced by a one half harmonic, using
the divide-by-2 circuit on the Al4 assembly. At the transitions between
subsweeps, the source is prettmed and then relocks lkble 12-3 lists the high
band subsweep frequencies from the fractional-N VCO and the source output.
A13/14
FRACTIONAL-N
--
TO 3GHz
ag6231d
Figure 12-5. High Band Operation of the Source
12-20 Theoryof Operation

HP 8753E Specifications

General

Brand	HP
Model	8753E
Category	Measuring Instruments
Language	English