Global Specialties 4005 - Manual - Manual (Page 16)

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3-4. Use as a Pulse Generator
In a symmetrical square wave, sine wave, or triangle wave, the positive and negative transitions are of
equal time duration, or 1:1 ratio. This condition is present when the SYMMETRY control is off. When
the SYMMETRY control is pulled and rotated, the positive transition can be stretched in relation to the
negative transition, up to at least, 10:1 ratio. Square waves can be stretched into rectangular waves or
pulses, triangle waves can be stretched into distorted wave shape called a skewed sine wave. FIG 5
illustrates the types of waveforms possible and includes a summary of control settings used to obtain
the desired waveform.
1) Procedure
A. Setup generator as described for function generator operation. Display the output of generator
on an oscilloscope.
B. Select the desired type of waveform with the Function Switches. Press the square wave button
for pulses, triangle button for ramp waves or sine wave button for skewed sine waves.
Figure 5. PULSE, RAMP, AND SKEWED SINE WAVE GENERATION
C. If both a specific pulse width and repetition rate (specific rise time and fall time for ramp wave)
are required, the waveform may be obtained as follows:
a. Adjust the shorter duration portion of the waveform (pulse width for pulse, fall time for ramp
waves) with the frequency controls FREQ dial and RANGE switch.
P u ls e
( S q u a r e )
R a m p
( T r ia n g le )
S k e w e d
( S in e )
T T L
S Y N C
A d ju s t P e r io d O f S h o r te r
D u r a tio n W ith F r e q . C o n tr o ls
A d ju s t P e r io d O f L o n g e r
D u r a tio n W ith
S y m m e tr y C o n tr o ls