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Chapter 5, FRONT PANEL OPERATION
Figure 5-14, Frequency Sweep Menu
The Frequency Sweep menu has nine controls affecting the instrument's internal
oscillator, and a link to the Curve Buffer menu (see section 5.3.24). Changes to the
setting of the controls can be made by using the adjacent
keys.
When a frequency sweep is run, the internal oscillator frequency starts at the defined
start frequency and is changed in discrete steps until it reaches the stop frequency.
Steps may be of equal size, which gives a linear relationship of output frequency to
time, or may be proportional to the present frequency, which gives a logarithmic
relationship. The controls operate as follows:-
OSC FREQUENCY
This control, which duplicates the Main Display OSC FREQUENCY control, allows the
instrument's internal oscillator frequency to be set to any value between 0.001 Hz
and 250.000 kHz with a 1 mHz resolution. Adjustment is faster using the Keypad or
Active Cursor controls - see section 4.1.04.
START FREQUENCY
This control defines the start frequency for the frequency sweep, which may be set to
any value between 0.001 Hz and 250.000 kHz with a 1 mHz resolution. Adjustment
is faster using the Keypad or Active Cursor controls - see section 4.1.04.
STOP FREQUENCY
This control defines the stop frequency for the frequency sweep, which may be set to
any value between 0.001 Hz and 250.000 kHz with a 1 mHz resolution. Adjustment
is faster using the Keypad or Active Cursor controls - see section 4.1.04.
STEP SIZE
This control defines the amount by which the oscillator frequency is changed at each
step. Depending on the sweep law selected (linear or logarithmic) it is set either in
hertz, or as a percentage of the present frequency. If Start Frequency is greater than
Stop Frequency then the output frequency will decrease with time.
TIME/STEP
This control defines the time that the oscillator frequency remains at each step of the
complete frequency sweep. The range of available values is 1 ms to 1000 s in 1 ms
increments.
5-19
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