Ametek 7280 Instruction Manual page 105

internal oscillator is set to 15 kHz, the unit will measure signals at both 1 kHz and
15 kHz. The Sensitivity 1, Time Constant 1 and Ref Phase 1 controls will affect the
signal being measured at 1 kHz, while the Sensitivity 2, Time Constant 2 and Ref
Phase 2 controls will affect the signal being measured at 15 kHz.
The range of controls that can be placed on the left-hand side of the Main Display
using the SELECT CONTROL key is therefore extended to include those relating to
both reference signals, as follows:-
SENSITIVITY 1
SENSITIVITY 2
When set to voltage input mode, using the Signal Channel menu, the instrument's
full-scale voltage sensitivity may be set to any value between 10 nV and 1 V in a
1-2-5 sequence.
When set to current input mode, using the Signal Channel menu, the instrument's
full-scale current sensitivity may be set to any value between 1 pA and 100 µA (wide
bandwidth mode), 10 fA and 1 µA (normal mode), or 10 fA and 10 nA (low-noise
mode), in a 1-2-5 sequence.
The number reported after the letters DR is the instrument's Dynamic Reserve,
expressed in decibels, as calculated by the following equation:-
DR 20 log
10
Example:-
If AC Gain = 14 dB and SEN = 2 mV then
DR 20 log
10
DR = 46 dB
TIME CONSTANT 1
TIME CONSTANT 2
The time constant of the output filters is set using this control, in the range 1 µs to
100 ks in a 1-2-5 sequence. Settings of 1 ms and below restrict the choice of
instrument outputs to X1/X2, Y1/Y2 and Magnitude1/Magnitude2.
REF1 PHASE
REF2 PHASE
These controls allows the reference phase of each detection channel to be adjusted
over the range -180° to +180° in 1 m° steps. Adjustment is faster using the Keypad or
Active Cursor controls - see section 4.1.04.
REF1 PHASE ±90°
REF1 PHASE ±90°
These controls allow the relevant reference phase to be adjusted in steps of ±90°.
Chapter 5, FRONT PANEL OPERATION
2
ACGain (in dB)
SEN
2
14
0.002
5-59