Lambda SR1, Operation Manual, Page: 67 / 317

SR1 Operation 67
© 2014 Stanford Research Systems
Amplitude control. The highest amplitude sample has the value given in the High Amplitude control.
The ramp waveform generates a generator trigger each time the ramp begins its rising
segment.
Arbitrary Waveform
The arbitrary waveform plays a sequence of values found in a user supplied table. Arbitrary waveform files
are simple ASCII files with one or more columns of floating point numbers representing the values of the
arbitrary waveform at each sampling interval.. Use the button to open a file dialog to select an
arbitrary waveform file. If multiple columns are detected in file, SR1 displays a dialog asking which
column to load. The number of table points read from the table is then displayed in the corresponding
control.
The amplitude entered in the Arb amplitude control is assigned to the maximum value found in the table.
The absolute scaling of the table values does not affect the output waveform. However, when operating at
arbitrary output rates the SR1 interpolates the user supplied table and normalizes to the peak
interpolated value thereby insuring that the peak amplitude remains constant at different output rates.
Thus the following table of values in the file:
0, 0.1, 0.2, 0.3, 0.4, 0.5,
produces a linear ramp from 0 to 0.2 FFS if the amplitude control is set to 0.2 FFS.
The Output Rate control governs how fast table points are output. At 100% the output rate is 1 table
point per output sample. At 200% the generator outputs every other table point each output sample. For
fractional output rates the waveform is interpolated. So at 50% Output Rate the generator outputs a table
point, then and interpolated point and then the next table point.
The arbitrary waveform generates a generator trigger each time the output returns to the
beginning of the table.