B&K Precision 4017A - Manual - Manual (Page 12)

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OPERATING INSTRUCTIONS
Figure 4. Effects of Symmetry
Variation.
6. Remember that the output signal swing of the generator is limited
to ±10 volts open circuited or ±5 volts into 50 Ω, and applies to
the combined peak-to-peak signal and DC offset. Clipping occurs
slightly above these levels. Fig. 3 illustrates the various operating
conditions encountered when using the DC offset. If the desired
output signal is large or if a large DC offset is required, an
oscilloscope
should be used to make sure that the desired signal
is obtained without undesirable clipping.
DUTY CYCLE CONTROL
The DUTY CYCLE control can be used to alter the symmetry of
the output waveform, to produce waveshapes such as those shown
in Fig. 4. For a square wave, symmetry variation amounts to
changing the duty cycle (ratio of "high" to "low" time), effectively
converting the instrument into a pulse generator. For a triangle
wave, the result is a ramp, and with a sine wave, a distorted
waveshape called a slewed sine is produced. The Model 4017A
provides for symmetry variation from 15% to 85%.
1. Select the waveform desired either SINE, SQUARE or
TRIANGLE.
2. Engage the DUTY CYCLE switch (17) and adjust the DUTY
CYCLE control (10) for the desired waveshape. Clockwise
rotation from center results in an increase in square wave duty
cycle, and changes the sine and triangle waves as shown in the
top waveform of each pair of Fig. 4. Counter-clockwise
rotation results in the bottom waveform in each pair.
3. Varying the duty cycle setting results in a slight change in
frequency. Adjust the COARSE and FINE frequency
controls as required.