UTILITIES
3-29
Frequency standard selection
(menu 1)
This utility enables you to select a 10 MHz output as a standard for use with associated equipment.
It also enables you to select a standard (either external or internal) for use by the instrument. When
an external standard is selected, the internal TCXO is locked to the external standard using a phase
locked loop. For a 10 MHz standard, the menu allows you to select between
dir
ect and
ind
irect.
When
direct
is selected the internal standard for the RF trays is provided directly from the external
standard. When
indirect
is selected this standard is provided from the TCXO locked to the
external standard. Frequency standard selection is as follows:
(1) Select
[Freq Standard]
to display the
Frequency Standard Selection Menu
shown in
Fig. 3-23 below. This shows the currently selected standard.
B3914
Fig. 3-23 Frequency standard selection menu
(2) Select the internal standard for the instrument by pressing
[10 MHz Int].
(3) To provide an externally generated 1 or 10 MHz standard for the instrument, connect the
signal to the rear panel EXT STD I/P socket. Then choose one of the three external standards
[10 MHz Ext Dir], [1 MHz Ext Ind]
or
[10 MHz Ext Ind].
You should choose
[10 MHz Ext
Dir]
if your provided 10 MHz standard is better than that fitted in the instrument.
(4) To obtain an internally generated 10 MHz standard from the instrument’s INT STD O/P
socket, select
[10 MHz Int Out].
(5) Press
[EXIT]
to return to the
Utilities Selection Menu 1.
