Stanford Research Systems SR785, Руководство по эксплуатации и программированию

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4-120 Swept Sine Average Menu
SR785 Dynamic Signal Analyzer
Command: SSCY (?) d {, i}
Integration Time
Set the Integration Time in increments of 3.906 ms [15.625 ms .. 1 ks].
At each frequency point, the inputs measure the signal at the source frequency. This is
done by multiplying the input data by the source sine (and cosine) wave and averaging
the results over an integration time. The actual integration time is always an exact
number of cycles at the source frequency. This rejects signals which are at a different
frequency, such as noise and harmonics. A long integration time results in a narrow
detection bandwidth at the source frequency. This improves signal to noise at the cost of
longer measurement times .
The Integration Time is converted to next largest number of exact cycles. The actual
number of integration cycles is the larger of the Integration Time (in cycles) and the
Integration Cycles. The integration time is always a minimum of 1 cycle or 15.625 ms.
To measure each point for the same amount of time (constant detection bandwidth), set
the Integration Cycles to 1 and the Integration Time to the desired time. The Integration
Time should be greater than 1 cycle of the lowest frequency in the sweep.
Changes made to the Integration Time during a sweep take effect immediately.
The estimated sweep time is displayed in the Horizontal Scale Bar. This time is simply
the sum of the Settle and Integrate times for all points in the sweep. Auto functions
(Source Auto Level, Auto Range, Auto Resolution) will change the actual sweep time.
Command: SITM (?) d {, x}
Integration Cycles
Set the number of Integration Cycles [1..32767].
At each frequency point, the inputs measure the signal at the source frequency. This is
done by multiplying the input data by the source sine (and cosine) wave and averaging
the results over an integration time. The actual integration time is always an exact
number of cycles at the source frequency. This rejects signals which are at a different
frequency, such as noise and harmonics. A long integration time results in a narrow
detection bandwidth at the source frequency. This improves signal to noise at the cost of
longer measurement times .
The integration time is an exact number of cycles. The actual number of integration
cycles is the larger of the Integration Time (in cycles) and the Integration Cycles. The
integration time is always a minimum of 1 cycle or 15.625 ms.
To measure each point for a time inversely proportional to the frequency, set the
Integration Time to 15.625 ms (minimum) and the Integration Cycles to the desired