Product Manual

Triggered Burst and Gate
Sync Out in Triggered Burst and Gated Modes 7
7-7
The phase can be set with a precision of 0·1 ° but the actual resolution is limited with
some waveforms and at certain waveform frequencies as detailed below. To indicate
when this is the case the actual phase is shown in brackets as a non-editable field below
the programmed value.
To achieve start phase precision all waveforms are run in clock synthesis mode, i.e. as if
they were arbitrary waveforms, when gated mode is specified; this limits actual
frequency resolution to 8 digits for all waveforms although the normally DDS generated
waveforms are still entered with 10−digit precision. Sine/cosine/haversine etc.
waveforms are created as if they were arbitrary waveforms with the first point of the
waveform exactly at the start phase; each time the phase or frequency is changed the
waveform is recalculated. This can cause a slight lag if the parameters are changed
quickly using the rotary knob.
The phase resolution of true arbitrary waveforms is limited by the waveform length since
the maximum resolution is 1 clock; thus waveforms with a length greater than 3600
points will have a resolution of 0·1 ° but below this number of points the maximum
resolution becomes 360 ° divided by the number of points.
Square waves, pulse, pulse trains and sequences have no start phase adjustment; phase is
fixed at 0 °. Refer to the table in the Triggered Burst section above for a summary of
start phase capabilities.
Sync Out in Triggered Burst and Gated Modes
When triggered burst or gated modes are selected the SYNC OUT source automatically
defaults to trigger; this is a positive-edged signal synchronized to the actual trigger
used whether internal (from the internal trigger generator or an adjacent channel) or
external of either polarity.
Alternatively, SYNC OUT can be set to burst done on the SYNC OUT set-up
screen; in this case it provides a signal which is low while the waveform is running and
high at all other times.