Operating instructions

University of Saskatchewan
Electrical Engineering Laboratory Equipment Manual
the time it takes the FFT processor to calculate the spectrum. With narrow spans, where
the time record is long then the processing time, the processor would calculate one FFT
per time record and wait till the next time record is completed. The update would be
slow. With overlap processing, data from the previous time record and the current time
record is used to calculate the next FFT. The overlap is a percentage of the time record.
No overlap is 0% and 99.8% reuses 511 out of 512 samples. The SR700 uses the
maximum amount of overlap allowed. This varies with the span. The analyzer uses
overlap processing in the continuous trigger mode only. No overlap is allowed, on spans
of 25KHz and over. The average menu may be used to enter a smaller overlap.
( Standford Research Systems, 2000 )