Jackson Labs PHASE STATION 53100A, Руководство пользователя

Страница: 128 / 225

PhaseStation 53100A User’s Manual V1.04 25-Apr-2022 128
Measurements in progress that have not been saved manually at least once, or that are
running with
Autosave interval set to a value less than one minute, will not be
automatically saved.
Enable deferred acquisition (
Ctrl-d
)
Trigger deferred acquisition(s) ( Enter )
Deferred acquisition
mode is toggled with the Enable deferred acquisition ( Ctrl-d )
command. In this mode, TimeLab will allow acquisitions to be launched as usual.
However, each new measurement’s incoming data will be discarded until all pending
measurements are
triggered. In deferred-acquisition mode, triggering occurs at the
expiration of a time interval specified in the
Acquisition options (
Ctrl-F7
)
dialog, when
the
Trigger deferred acquisition(s) (
Enter
)
command is issued, or when another
Enable
deferred acquisition ( Ctrl-d ) command is issued to return to immediate-acquisition
mode. Data will subsequently be collected normally for the duration of the
measurement(s).
Deferred-acquisition mode can be useful when you wish to launch multiple concurrent
acquisitions – perhaps using different types of instruments with varying latency or setup
time requirements – while synchronizing the beginning of data collection as closely as
possible across all measurements. Another common application for deferred
acquisition is to wait for a given stabilization period to elapse after the instrument’s
attenuators and filters are configured at the beginning of the measurement process.
Load impedance will be relatively constant at all times when using the ‘N’ female
REFERENCE and DUT input jacks on the 53100A, due to the inherent isolation
characteristics of the built-in active splitters. However, multichannel measurements will
expose the reference and DUT sources to varying load conditions at the SMA-F channel
input jacks during the startup phase, so deferred acquisition can be a useful tool in
these cases.
Note that TimeLab doesn’t specify the trigger latency associated with a group of
deferred measurements. Triggered measurements made with time interval counters
will normally start collecting valid data within one sample period, but this isn’t
guaranteed.
Also note that the DUT frequency is initially measured when the measurement begins,
not when it is triggered. Attempting to measure an oscillator undergoing startup drift in
a narrow measurement bandwidth will usually yield drift warning messages and
questionable data regardless of the use of deferred acquisition. Always ensure that the
measurement bandwidth is sufficiently wide to keep the DUT signal well within its
passband during the deferral period, as well as the remaining duration of the
measurement itself.