Synthesized Lo Source Timebase Check And Adjustment; Description And Procedure - HP 85325A Operating And Service Manual

R/q/u/v/w millimeter subsystem, millimeter-wave interface kit

Hide thumbs

Table Of Contents

Table of Contents

Description and

Procedure

Table 5-1

Synthesized LO Source Timebase Check

and Adjustment

This adjustment only needs to be performed when:

•

the LO is an HP 8560 series source and,

•

there is no 10 MHz reference connection between the LO and RF

source.

This procedure adjusts the frequency accuracy of the internal 10 MHz

timebase of the LO source. This adjustment should be done on a regular

basis if you cannot connect the timebases (LO, RF, and receiver) together.

This adjustment procedure should be done at least once a year. Millimeter

wave systems should be done more often.

Table 5-1 shows the required adjustment interval to maintain a given

accuracy. If you know the aging rate, you can determine a more precise

adjustment interval. See the HP 8360 series synthesizer service manual for

more information.

Suggested Adjustment Interval for LO Sources

Highest Frequency Tested

< 26.5 GHz

Between 26.5 and 50 GHz

Between 50 and 110 GHz

For the best accuracy, readjust the 10 MHz timebase oscillator after the LO

source and RF source have been ON or in STANDBY for 24 hours. After the

LO source timebase is adjusted, the timebase frequency should stay within

the aging rate if the following things happen:

•

The timebase oven does not cool down.

•

The instrument stays at the same altitude.

•

The instrument does not receive any mechanical shock.

•

The instrument keeps the same orientation with respect to the earth's

magnetic ﬁeld.

If the timebase oven cools (the instrument is disconnected from ac power),

you may have to readjust the timebase frequency after a new warm-up cycle.

Typically, however, the timebase frequency returns to within

original frequency.