Lambda SR1, Operation Manual, Page: 172 / 317

SR1 Operation Manual 172
© 2014 Stanford Research Systems
Histogram of 1 kHz Digital Sine
The first histogram shows a 997 Hz digital audio sine wave with a sampling frequency of 48 kHz.
Because the sampling frequency is not a multiple of the signal frequency each cycle of the digital audio
sine uses slightly different values and the result is a histogram with a smooth continuum of amplitudes
between ±1 FFS. If the sine frequency is shifted slightly to 1 kHz, the histogram changes radically. Now
the sampling is a multiple of the signal frequency and each cycle of the sine repeats a finite set of
exactly the same values. The "discrete" nature of the 1 kHz sine is easily seen on the histogram even
though the two signals would have similar spectra if viewed with the FFT analyzer. In general, the
histogram analyzer can reveal details of a signal's quantization that are not apparent with time or
frequency domain analysis.
Histogram Analyzer Panel