Stanford Research Systems SR780, Operating Manual And Programming Reference

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Swept Sine Source Menu 4-67
SR780 Network Signal Analyzer
Swept Sine Source Menu
The Source menu sets the source amplitude parameters when the Measurement Group is
Swept Sine. See ‘Swept Sine’ in Chapter 2 for a discussion about swept sine
measurement fundamentals.
Auto Level Reference
Select the Auto Level Reference mode [Off, Channel 1, Channel 2].
Auto Level Off maintains the source amplitude at a constant level at all frequencies
during the swept sine sweep. This usually works best for transfer functions which are
fairly flat.
Auto Level Channel 1 or 2 will adjust the source level to maintain a constant level, called
the Ideal Reference, at the Channel 1 or Channel 2 input. Generally, this is useful for
transfer functions with substantial gain as well as attenuation. Input Auto Ranging is
turned on for both inputs when Auto Level is on. Whenever Auto Level is used, the
measurement MUST be transfer function.
The Auto Level Reference Channel determines which input will be maintained at the
Ideal Reference Level. This is usually the device under test output (Channel 2). In some
cases where the device under test is not driven directly from the source output, the device
input (Channel 1) may be the reference.
Command: SSAL (?) {i}
Amplitude
Set the sine Amplitude [0 mV .. 5000 mV]. This parameter is adjustable only if Auto
Level Reference is Off.
The swept sine source turns off whenever there are no measurements being made. This is
before the sweep is started, at the end of a single sweep or while a sweep is paused. If