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Model 8642A/B
Operation
KNOB
Description
The Knob is a variable stepping control. It actually changes the active function in steps
that are determined either by 1) the cursor position and the rate at which you turn the
Knob or 2) the increment set value if the Knob Increment function is selected. The
Knob can control the following functions:
Frequency
Start Frequency
Stop Frequency
Amplitude
Start Amplitude
Stop Amplitude
AM Depth
FM Deviation
<I>M Deviation
Modulation Frequency
Modulation Output
Sweep Time
Manual Sweep (for either amplitude sweep or frequency sweep)
Help
Phase on Knob and Step keys, (Special Function 250)
Knob Hold enables the Signal Generator to fix the Knob control on a function even if it
is no longer the active function. With Knob Hold, the Step keys and Data keys enable
control of the new active function while allowing the Knob to continue control of the
"held" function.
While Knob Increment is selected, the Knob is less sensitive to the Knob rotation rate in
affecting how much a setting is changed as the Knob is turned. This gives you the
capability to make individual precise steps with more control, using the Knob.
Procedures
The Signal Generator powers up with the Knob function enabled with RF frequency as
the active function. Therefore, unless the Knob is disabled (for example, by selecting
ENTRY OFF ( I SHIFT I I RF OFF/ON I ), any rotation of the Knob changes the value
of the active function.
Note: Put the instrument in its initialized state by selecting 1 INSTR PRESET T.
How to Control Knob Resolution Using the Cursor Positioning Keys
The cursor position specifies the Knob resolution (unless Knob Increment is selected).
For example, a cursor above the 2 in a 260 HZ FM display indicates that the Knob will
change the FM value in 100 Hz steps. You can re-position the cursor with the [ - I and
[ - I keys to change Knob resolution by a factor of ten.
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