Agilent Technologies N5230A, Руководство по обслуживанию, Страница: 130 / 262

5-10 Service Guide N5230-90014
Theory of Operation PNA Series Microwave Network Analyzers
Synthesized Source Group Operation N5230A
A10 Frequency Reference Board
This assembly provides stable reference frequencies to the rest of the instrument. A high
stability 10 MHz oven-controlled crystal oscillator (OCXO) normally provides the
frequency standard. However, if a 10 MHz external reference signal is detected at the
10 MHz EXT REF IN port on the rear panel, it is used as the frequency reference instead.
The 10 MHz reference signal is used to phase lock a 100 MHz VCO. The output of this VCO
is then divided by ten to produce the 10 MHz EXT REF OUT rear panel signal. This
10 MHz signal is divided by two to produce 5 MHz reference signals for the A5 signal
processing ADC module (SPAM) board, the A7 fractional-N synthesizer board, and the
A9 fractional-N synthesizer board.
Rear-Panel Interconnects
10 MHz REF. INPUT A BNC connector that allows an external frequency reference
signal to be used to phase lock the analyzer for increased
frequency accuracy.
The analyzer automatically enables the external frequency
reference feature when a signal is connected to this input. When
the signal is removed, the analyzer automatically switches back to
its internal frequency reference.
10 MHz REF. OUTPUT A BNC connector that allows a 10 MHz reference signal, produced
by the A10 frequency reference board, to be output for use in
phase locking external test equipment.