Stanford Research Systems SR785, Operating Manual And Programming Reference

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4-72 Chirp Source Menu
SR785 Dynamic Signal Analyzer
Offset
Set the DC Offset of the Sine Source [-5V..5V]. The offset resolution is 0.1 mV. The
sine output is the sum of two tones (sine waves) and the offset (constant). Note that the
sum of the amplitudes of Tone 1, Tone 2 and the absolute value of the offset cannot
exceed 5 V.
Using large offsets with small tone amplitudes will degrade the distortion performance of
the sine source.
Command: SOFF (?) {x}
Tone 2
Display the Tone 2 Settings menu. Press <Return> for the main [Source] menu.
Frequency 2
Set the Frequency of Tone 2. The sine output is the sum of two tones (sine waves). When
the knob is used to adjust the frequency, the resolution is equal to the Linewidth of the
active display FFT Span. The knob always sets the frequency to an exact multiple of the
Linewidth. For octave analysis, the Linewidth of the most recent FFT Spans are used
(with an FFT Base of 100.0 kHz).
The keypad allows arbitrary frequencies to be entered. Remember, the output is periodic
over the FFT time record only if the frequency is an exact multiple of the Linewidth.
Source Trigger will not result in a stable phase for non-periodic frequencies.
The sine source is not triggered. The output is always continuous.
Command: S2FR (?) {f}
Amplitude 2
Set the Amplitude of Tone 2 [0..5V]. The amplitude resolution is 0.1 mV. The sine
output is the sum of two tones (sine waves) and the DC offset (constant). To generate a
single tone, set the amplitude of one of the tones to zero. Note that the sum of the
amplitudes of Tone 1, Tone 2 and the absolute value of the offset cannot exceed 5 V.
Command: S2AM (?) {x}