Inter-Module Synchronization; Synchronization - Racal Instruments 3151 User Manual

3151 And 3151A User Manual
Inter-Module

Synchronization

Synchronization Although multiple Model 3151/3151As within one chassis run off a
common clock (CLK10), their outputs are not synchronized to each
other. If the same waveform length and clock rates for two modules
are selected and both are displayed on an oscilloscope, the outputs
may look as though they are synchronized even though they are not.
The waveforms may not start at the same point along the waveform.
If another waveform is selected or if the same waveforms are
reprogrammed, you may notice that the phase relationship between
the two modules has changed again.
Phase synchronization requires the use of the VXI
ECLTRG0 and ECLTRG1 signals. Other VXI instruments
must not drive ECLTRG0/1 while phase synchronization
is enabled.
There are phase synchronization commands that can tightly control
phase offsets between two or more Model 3151/3151As. These
commands are described below. To use the following commands,
two Model 3151/3151As are required. When synchronizing
modules, the waveforms in each module must have exactly the
same number of points.
First, load the waveforms in all the modules in preparation for phase
synchronization. Then select one Model 3151/3151A as master and
program it using the following commands:
PHASe:LOCK ON
PHASe:SOURce MAST
The above Model 3151/3151A is now programmed as master. Next,
program the other Model 3151/3151A modules as slaves (SLAVe)
and program their phase offset in relation to the master. As an
example, program the second and third Model 3151/3151A with 120
and 240 degrees offsets, respectively.
Use the following commands on the second Model 3151/3151A:
PHASe:SOURce SLAVe
PHASe:LOCK ON
CAUTION
Using The Instrument 3-39