HP 8530A, Руководство по эксплуатации и программированию, Страница: 171 / 439

Angle Domain Stimulus Controls
Setting Increment Angle
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INCREMENT ANGLE , coupled with the Start and Stop Angle , tells the receiver how many points
of data it should acquire during the measurement.
F or example , assume you select the following:
Start Angle: 090
Stop Angle: +90
Increment Angle: 1
This measurement would result in 181 points of data. In this case the receiver knows it must
take 181 points of data before the measurement is nished. If you are using external trigger
mode (with triggers sent by the positioner controller), the receiver will expect 181 triggers
before the measurement is nished. Refer to the section on External Triggering (later in this
chapter) for more details .
Remember , the receiver does not control the positioner controller . The receiver depends on the
trigger pulses from the positioner controller (or on HP-IB GET commands from a computer)
to know exactly when data should be acquired. Also , the receiver has no way of knowing
the actual direction the positioner is pointing. The receiver assumes that the positioner is
at the start angle when the rst trigger occurs . Be sure that the rst trigger occurs when the
positioner is at the start angle . In the above example this would be at -90 . Triggers occurring
before this will cause the receiver to start the measurement too early .
F or example , assume that a certain positioner controller issues a trigger pulse at 091 . The
receiver would take one point of data and assume that it applies to the start angle (090 ).
The measurement would continue , with data being oset by 1 throughout the rest of the
measurement (this example assumes the increment angle is set to 1 ).
Example of Use:
Press
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INCREMENT ANGLE 2 4 x1 5 if the positioner controller is set to an increment angle of 2
degrees . T erminate Increment Angle entries with one of the following terminator keys:
4 k/m 5 millidegrees
4 x1 5 degrees
Selecting Sweep Mode (single or swept angle)
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SINGLE ANGLE and
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SWEPT ANGLE determine whether the receiver will acquire data at a single
angle , or over a span of angles . These two softkeys are toggles , selecting one turns the other
OFF .
Use Single Angle mode to boresight an antenna. Use Swept Angle mode to make pattern
measurements .
6-4 Stimulus Functions