Lambda SR1, Руководство по эксплуатации, Страница: 173 / 317

SR1 Operation 173
© 2014 Stanford Research Systems
Sample Rate
The Histogram Analyzer can examine each sample in the input data stream, or it can examine only
every other, every 4th, etc. up to every 512th sample. Use the Sample Rate drop-down to control the
fraction of points in the input record which are included in the histogram.
Histogram Size
The Histogram Size control determines how many input points are examined for each histogram. This
number does not include points which are skipped as a result of the Sample Rate selection. Remember
that this control only determines how many input points are looked at— if all the points lie outside of the
histogram range the histogram can still have 0 counts in each bin even though the histogram size is set
to 16k.
Histogram Scale
The scale controls determine the upper and lower voltage limit for the histogram. There is no need for the
limits to be symmetric. Pressing autoscale automatically sets the upper and lower histogram limits to
the current analog input range (if analog inputs are selected). If the selected domain is digital the limits
are set to ±1.414 FFS. The amplitude space between the upper and lower limits is divided into the
number of bins selected with the "Bins" drop-down. Values between 16 and 512 bins are allowed.
Histogram Averaging
Successive histograms may be averaged. When "Continuous" averaging is selected each new histogram
is averaged with the previous results in a manner that weights more recent histograms more strongly
than older ones. The averaging process is updated continuously. "Single" averaging averages N
histograms all weighted equally (where N is selected with the "# Avgs" control) and then stops
acquisition. Press "Clear" at any point to clear the averaging buffer and re-start the averaging process.