Reference Channel Menu - Ametek 7280 Instruction Manual

AUTO AC GAIN OFF
In this setting the AC Gain may be manually adjusted from the Main Display.
AUTO AC GAIN ON
In this setting the AC Gain value is automatically selected by the instrument,
depending on the full-scale sensitivity. In the mid-range full-scale sensitivity
ranges the resulting dynamic reserve is between 20 and 26 dB.
Pressing the Previous Menu key returns control to Main Menu 1.

5.3.05 Reference Channel Menu

When Main Menu 1 is displayed, pressing a key adjacent to the Reference Channel
item accesses the Reference Channel menu, which is shown in figure 5-7.
The Reference Channel menu has five controls affecting the instrument's reference
channel. Changes to the setting of these controls can be made by using the adjacent
keys.
REF SOURCE
This control allows selection of the source of reference signal used to drive the
reference circuitry, and has three settings:-
INT
The lock-in amplifier's reference is taken from the instrument's internal oscillator.
Note that this setting gives the best phase and gain measurement accuracy under
all operating conditions, and it is always to be preferred, if possible, to design the
experiment so that the lock-in amplifier acts as the source of the reference signal.
EXT-R
In this setting the reference channel is configured to accept a suitable external
reference source applied to the rear panel REF TLL input connector
Chapter 5, FRONT PANEL OPERATION
Figure 5-7, Reference Channel Menu
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