OPERATING INSTRUCTIONS
4. Connect a suitable modulation signal to the
VCG/MOD
INPUT
jack on the front panel.
5. Adjust the amplitude and frequency of the external
signal as required. Typically, a signal less than 10V p-
p will provide 10% modulation of the carrier.
TTL/CMOS OUTPUT
The
TTL/CMOS
output jack provides a fast rise time
square wave output. Either a fixed TTL or a variable CMOS
output level is available. The output is positive with respect
to ground and can be used as an external sync pulse for
oscilloscopes or as a variable frequency signal source for
exercising logic circuits. Because of the fast rise time of this
output, cable length should be minimized to limit ringing and
overshoot.
1. Select the desired frequency range and adjust the
frequency controls as required. The
OUTPUT LEVEL
and
DC OFFSET
controls have no effect on the signal
at the TTL/CMOS jack.
2. When the
CMOS LEVEL
switch (3) is released, a TTL
signal is output at the
TTL/CMOS
jack. Select a CMOS
signal by engaging the
CMOS LEVEL
switch and adjust
the level of the signal by rotating the
CMOS LEVEL
control (8).
VOLTAGE CONTROLLED FREQUENCY OPERATION
The
Model 4040A
can be operated as a voltage-controlled
generator by using an external control voltage applied to the
VCG/MOD INPUT
jack (12). The externally applied voltage
will vary the frequency which is pre-selected by the range
switches and the frequency controls. Applying
approxil0 V with the
COARSE
control at full
clockwise decreases the output frequency by about 100
times (a 100:1 ratio).
1. Select the desired frequency range and waveform.
2. Set the starting frequency with the
COARSE
control.
Apply a positive DC voltage to the
VCG/MOD INPUT
jack (l2) to decrease the frequency. A voltage from 0 to
+10 V will cause the frequency to decrease by a factor
of 100 if the
COARSE
frequency control is set at
maximum CW rotation. For example, if the starting
frequency is 100 kHz, ap10 V will change the
output frequency to 1 kHz.
3. To operate the function generator as a sweep
generator, apply a positive-going ramp signal to the
VCG/MOD
input jack. As the ramp voltage increases,
the frequency decreases. The rate of sweep can be
adjusted by varying the frequency of the ramp signal.
4. Specific frequencies can be selected by applying a
fixed dc voltage to the
VCG/MOD INPUT
jack or the
frequencies can be stepped by applying a stepped dc
voltage.
5. Do not apply more than ±15 volts (dc or dc + ac peak)
to the
VCG/MOD INPUT
jack. Inputs of more than 15
volts will not cause any further shift in the frequency
and could cause damage to the generator.
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