Lambda SR1, Operation Manual, Page: 285 / 317

SR1 Operation 285
© 2014 Stanford Research Systems
2.9.4 Digital-Digital
The Digital-Digital selection lists measurements with both a digital stimulus and response. The outputs
and inputs are set to the XLR connector. The output sampling rate is defaulted to 48 kHz.
What you'll need to configure for all these setups:
Change the digital input and output settings to match the equipment being tested,
FFT
This setup configures SR1 for a basic audio band FFT. The Hi-resolution converter is selected for
maximum dynamic range. The A0 analyzer is configured as a dual channel FFT analyzer with a span of
28.8 kHz and continuous averaging.. The Analog Generator is loaded with a low-distortion sine waveform
set to a default frequency of 1 kHz and an amplitude of 1 FFS. Page2 contains a graph displaying the A
and B channel power spectra while Page 3 contains a graph displaying the A and B channel time
records.
What you'll need to configure:
If you're using the digital generator, adjust the amplitude and frequency of the signal to match your
requirements. Otherwise you can turn the generator off. The amount of
averaging in the FFT analyzer can
be adjusted to suit the noise level of your signal. The FFT resolution is defaulted to 2k points, this can
be adjusted.
Frequency Response
This setup configures SR1 for a stereo audio-band frequency response sweep. The Time Domain
Detector is selected for the A0 analyzer. The Digital Generator is loaded with a sine waveform. Page2
contains a graph displaying the A and B channel frequency response. The sweep controller is
programmed to sweep the sine frequency from 20 Hz to 20 kHz in 22 logarithmic steps and record the A
and B channel levels.
What you'll need to configure:
Adjust the the sine amplitude to match the equipment being tested. The number of points in the sweep
can be changed to give faster sweeps or higher resolution sweeps. The settling parameters can be
adjusted to fit the noise levels of the signals being measured.
THD+N vs. Amplitude Sweep
Performs a THD+N vs. amplitude stereo sweep. The A0 and A1 analyzers are set to Time Domain
Detector in order to measure THD+N. A digital 1 kHz sine waveform is setup with an amplitude sweep
range of 1 mFFS to 1 FFS in 22 logarithmic steps. Page 2 displays a graph of the A and B channel
THD+N vs. Amplitude.
What you'll need to configure:
The default frequency is 1 kHz. This should be adjusted as needed. The settling parameters can be
adjusted to fit the noise levels of the signals being measured.The bandwidth of TDD can be adjusted to
suit the measurement requirements.
THD+N vs. Frequency Sweep
Performs a THD+N vs. frequency stereo sweep. The A0 and A1 analyzers are set to Time Domain