for ramp waves)with the SYMMETRY control.
D. If a specific pulse width (specific fall time for ramp wave)is not critical, but a
specific repetition rate is required, the desired waveform may be obtained as
follows;
a. Observe the oscilloscope and adjust the SYMMETRY control to obtain the
approximate desired pulse width vs. rest time ratio(rise time vs. fall time ratio for
ramp waves).
b. Adjust the repetition rate with the frequency controls FREQ. dial and RANGE
switch. the frequency controls affect both the pulse width and repetition rate.
3-4-2. Considerations
A. When generating ramp waves or skewed sine waves, it may be easier to
measure the time periods on oscilloscope using the square wave mode, then switch
to the desired operating mode.
B. For ease and accuracy in measurement, use a higher sweep speed on the
oscilloscope to expand the pulse width for measurement, then reduce sweep speed
to measure the repetition rate.
C. Repetition rate may be expressed as a frequency or time period. Measure the
repetition rate as a time period on oscilloscope and convert to frequency if required.
The repetition rate includes the full cycle, both the pulse width and rest time for
pulses, the rise time and fall time for ramp waves.
D. Repetition rate can be measured accurately and easily as a frequency or time
period with a frequency counter.
E. Pulse width also can be measured on a frequency counter, but only with the
SYMMETRY control set off before the pulse waveform is “stretched”. Pulse width
equals one-half the time period of the square wave. If the counter is not equipped
for period measurement, calculate the frequency, which is equivalent to the desired
pulse width, and measure the frequency of the waveform.
1
DESIRED PULSE WIDTH x 2
3-5. TTL/CMOS OUTPUT
TTL/CMOS output is specifically designed for compatibility with TTL/CMOS digital
logic circuits. Set-up time is considerably reduced because the fixed logic levels
and polarity are ready for direct injection into TTL/CMOS circuits. there is a need for
protection from accidental Application of too high amplitude or incorrect DC offset
which might damage semiconductors. Another advantage is the extremely fast rise
time and fall time of signal. To use the TTL/CMOS output, connect a cable from
TTL/CMOS BNC on the Front panel to the point at which it is desired to inject the
signal. TL/CMOS output may be used in several modes of operation. Some
examples follow.
A. Using the square wave generator or pulse generator modes, clock pulses can be
generated for testing, troubleshooting or circuit analysis. The instrument could even
be used as a substitute master clock generator as TTL/CMOS circuits can be driven
from the TTL/CMOS BNC.
B. The CMOS Level Control potentiometer (pull out position) provides CMOS level
output from 5V to 15V Variable and Continuously. For TTL/CMOS output level,
Rotate the potentiometer switch and Observe the TTL or CMOS output : Push-in is
TTL, Pull-out is CMOS.
DESIRED FREQUENCY =
