Low Duty Cycle Pulse Trains; Multiple Pulses - Metrix GX1010 Notice De Fonctionnement

Using this technique the duty cycle range is limited to that achievable with the symmetry
control (99:1). For very small duty cycles, at lower repetition rates, the triggering facilities
may be used, see next section.

6.3.1. Low Duty Cycle Pulse Trains

These can be created by using the internal trigger generator to produce the long interval
between the pulses, with each pulse being a single cycle of the main generator. Set the
main generator to 10kHz by pressing FREQ, 1, 0, kHz, and reduce the duty-cycle to 1:99
(i.e. pulse width 1µs) by pressing SYM, 1, %.
Select the Trigger menu by pressing EDIT, TRIG, and set SOURCE = TGEN, i.e. internal
trigger generator. The TGEN period should be at its default setting of 1·00ms (1.000kHz)
and the burst count set to 0001. The default phase setting of 0° corresponds to the top of
the rising edge of the pulse and starting at this phase will not give the desired result; set
the phase to -90° by moving the cursor to the PHASE field with the FIELD keys and enter -,
9, 0, CONFIRM.
Whilst still in the Trigger menu press TRIG again to turn Trigger mode on.
A single cycle of the main generator (i.e. a single pulse) will now be output at the default
frequency of 1kHz; a 1000:1 duty cycle has now been achieved. Move the cursor to the
TGEN period field with the FIELD keys and increase the period using the rotary control;
although it will be difficult to see on the oscilloscope, the 1µs pulsewidth is maintained
down to mHz repetition rates, i.e. a very small duty-cycle.
Note that at Main generator frequencies above 30kHz phase control of pulse waveforms is
restricted unless waveform generation is in Low Frequency mode, see Waveform
Generation Options section; this ultimately limits how narrow a pulse can be generated at
very low repetition rates.

6.3.2. Multiple Pulses

Multiple pulse trains are obtained by using the same trigger set-up as above but with the
burst count set to the desired number of pulses.
54 - II GX1010