Fluke 291 User Manual page 79

291, 292, 294
Users Manual
ARB CLOCK IN/OUT socket, or to the system clock on multi-channel instruments. To
select external clock mode press the PULSE PERIOD soft key on the
PULSE PERIOD screen (or the PULSE FREQ soft key on the PULSE FREQ
screen) to change from internal to external clock. The screen changes to, for example:
on a single-channel instrument, or
on a multi-channel instrument. It is then possible to select the source to be either an
external signal on the ARB CLOCK IN/OUT socket or the internal system clock; see the
Reference Clock IN/OUT and System Clock Setting sections of Chapter 15, System
Operations from the Utility Menu for the use of and frequency setting for the system
clock.
Note that the pulse waveform will continue to run from the internal clock until the
instrument receives the first rising edge of the external clock; at that point the hardware
switches over to the external source. In external clock mode the period of the pulse
waveform is determined by the number of points in the waveform multiplied by the
period of the external clock. The external clock period is determined by the user; the
number of points in the pulse waveform can be found, before selecting external clock,
by pressing the set-up soft key beside pulse on the STANDARD WAVEFORMS screen.
Pulse-Train Set-Up
Pulse-trains are turned on with the pulse-train soft key on the STANDARD WAVEFORMS
screen; pressing the setup... soft key beside pulse-train calls the first of the set-up
screens:
The number of screens used for the set-up depends on the number of pulses in the pulse-
train. The first three screens define the parameters that apply to the whole pattern
(number of pulses, overall pulse-train period and baseline voltage); subsequent screens
define the pulse level, width and delay for each pulse in turn (three screens for pulse 1,
then three screens for pulse 2, etc.).
10-4
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PULSE PERIOD: ext
source: ext arb clk
PULSE PERIOD: ext
source: ext arb clk
freq: 10.0000000kHz
Enter no of pulses
in train (1-10):
2
done next
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