64
mode: indep
◊
phase: +000.0
°
(actual: +000.0
°
)
◊
status: off view
◊
The phase of the
slave generator
is set by adjusting the phase of the
master channel
on the
slave generator’s Inter
−
channel set
−
up screen exactly as described in the Phase
−
setting
between Channels section of the inter
−
channel Synchronisation chapter. The phase(s) of slave
channel(s) on the slave generator are set up with respect to the master in the way described in
that same section.
When a single generator, which has no Inter
−
channel set
−
up key or screen, is the slave, its
phase is set on the TRIGGER/GATE SETUP screen, see Trigger Phase section of the Triggered
Burst and Gate chapter.
The convention adopted for the phase relationship between generators is the same as that used
between channels, i.e. a positive phase setting advances the slave generator with respect to the
master and a negative setting delays the slave generator. The status of the slave generator on
the inter
−
channel set
−
up screen must be set to on (automatic on a single channel generator).
Hardware delays become increasingly significant as frequency increases causing additional
phase delay between the master and slaves. However, these delays can be largely nulled
−
out by
‘backing
−
off’ the phase settings of the slaves.
Typically these hardware delays are as follows:
DDS waveforms:
<± 25ns; <1
°
to 100kHz
Clock Synthesised waveforms: <300ns; <1
°
to 10kHz.
Clearly a multi
−
channel generator gives much closer inter
−
channel phase
−
locking and is the
recommended method for up to 4 channels.
Synchronising
Having made the connections and set up the generators as described in the preceding
paragraphs, synchronisation is achieved by pressing the MAN TRIG key of the slave. Once
synchronised any change to the setup will require resynchronisation with the MAN TRIG key
again.
