Programmed Frequency Selection; Use As Sweep Generator - UNISource Corporation FG-8102 Operation Manual

C. The FREQ. dial is usually set to 0.02 when using external VCF control. This
reduces the dialed VCF voltage to zero and allows the external VCF voltage
to exercise complete control. It also reduces the effects of dial setting
inaccuracy.
D. If the summed dial setting and VCF IN voltage exceeds +10 volts, oscillation
ceases and no output is produced. If the swing of the VCF IN signal is too
great, oscillation will cease each time the instantaneous voltage reaches the
limit.

3-8. Programmed Frequency Selection

A specific output frequency can be selected each time a specific VCF input
voltage is applied(assuming a common dial setting). Such operation may
be advantageous where there is a requirement to return to a specific
frequency periodically. Eliminating the need for frequency measurement
reduces set-up time and precision tuning each time frequency is needed.
Just set the dial against its lower stop and turn on the external VCF
voltage. Using multiple DC voltage values, which may be selected by a
switch or electronic switching circuits, may program a set of two or more
specific frequencies. This type of operation would be desirable in
production testing where signals at several specific frequencies are
required for various tests. FSK(frequency shift keying)signals also may be
generated in this manner. To maintain the original accuracy each time the
operation is repeated, the FREQ. dial must be accurately set to the same
position. Probably the easiest way to assure this common dial setting is to
set it against its lower stop. Additional information on programmed
frequency selection is given in APPLICATIONS chapter of this manual.

3-9. Use As Sweep Generator

1) Procedure
A. Set up equipment as for function generator operation.
B. Select the highest frequency to be swept with RANGE switch and the
lowest frequency to be swept with FREQ. dial.
C. Adjust amount of sweep with the sweep rate control.
D. Adjust repetition rate of sweep with the sweep rate control.