Connections For Synchronisation; Generator Set-Ups; Synchronising - Metrix GX1010 Notice De Fonctionnement

4.10.2. Connections for Synchronisation

The preferred clock connection arrangement is for the rear panel CLOCK IN/OUT of the
master (which will be set to CLOCK OUTPUT) to be connected directly to each of the
CLOCK IN/OUT sockets of the slaves (which will be set to PHASE LOCK). The alternative
arrangement is to 'daisy-chain' the slaves from the master using a BNC T-piece at each
slave connection but reflections can cause clock corruption at the intermediate taps under
some circumstances.
Similarly the preferred synchronising connection is from the rear panel SYNC OUT of the
master directly to each of the EXT TRIG inputs of the slaves. The alternative arrangement
is to 'daisy-chain' from each SYNC OUT to the next generator's EXT TRIG in turn; this
does not give rise to any data integrity problems but cumulative hardware delays will
worsen the phase-shift accuracy.

4.10.3. Generator Set-ups

Each generator can have its main parameters set to any value, with the exception that the
ratio of frequencies between master and slave must be rational, see Synchronising
Principles section. Each generator can be set to any waveform.
The phase relationships between the slaves and the master are set individually on the
Trigger menus of each slave, exactly as described in the Triggered burst section. The
convention adopted in Synchronised mode is that a negative phase setting delays the
slave output with respect to the master; for example, a phase setting of -90° will delay the
slave by a quarter-cycle with respect to the master. If the slave's EXT TRIG inputs are all
driven directly from the master then all phase shift is referenced from the master; thus 4
generators set to the same frequency with the 3 slaves set to -90°, -180° and -270°
respectively will give four evenly spaced phases of the same signal. If, however, the
synchronising signal was daisy-chained from each SYNC to the next generator's EXT TRIG
then the phase shifts become cumulative and each slave must be set to -90° phase to
achieve the same result.
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.
The phase setting on each slave affects the AUX OUT phase as described in the Auxiliary
Output section. Note though that the phase setting for synchronisation purposes is not
subject to the same waveform dependent frequency limitations as AUX OUT.
The individual modes for the master and slaves are set in the CLOCK BNC field of the
SYStem menu, see System Settings section. The master is set to CLOCK BNC = OUTPUT
and all the slaves are set to CLOCK BNC = PHASE LOCK.

4.10.4. Synchronising

Having made the connections and set up the generators as described in the preceding
paragraphs, synchronisation is achieved by pressing the MAN/SYNC key of each slave in
turn. Once synchronised only the clock connections need be maintained; however, any
change to the set-up of a slave, e.g. a phase change, will cause synchronisation to be lost
as the waveform memory is rewritten with the new phase, etc., and re-synchronisation will
be necessary.
36 - II GX1010