3152A User Manual
Racal Instruments
©
2001
Using The Instrument 3-47
CAUTION
The PHASe:NULL command toggles between
removing one count and adding one count.
Therefore, if there was no error, sending this
command may add a 1 count error.
The query:
PHASe:LOCK?
queries the Phase Lock mode and returns "0" (OFF) or "1"
(ON).
The query:
PHASe:ADJust?
queries the phase offset and returns a value in degrees.
In query:
PHASe:SOUR?
queries the phase lock source and returns MAST or SLAV.
Front-Panel Phase
Synchronization
The Model 3152A can phase lock to an external reference
which is applied to the trigger input. The locking process is
done automatically by the generator. There is no need for the
user to initiate or set the generator’s lock-in range for this mode.
A front-panel LED illuminates when the reference signal is valid
and the Model 3152A locks on the external signal. After lock
has been achieved, you may shift the phase between the
reference and the generator from -180
o
to +180
o
.
NOTE
Phase offset resolution depends on the number of
waveform samples. For instance, if you have 1000
waveform samples, there is no problem with
adjusting the phase offset in 1
o
increments (360
o
/
1000 < 1). As another example, if you have only 10
waveform samples, the best phase offset
increments are only 36
o
(360
o
/ 10 = 36
o
).
There is a special fine adjustment for phase offset with a 36
o
range. This adjustment is useful in places where a 36
o
gap is
too wide. The fine phase adjustment improves phase offset
settings to 0.01
o
and can be used in conjunction with the coarse
phase offset adjustment at any phase offset setting point.