Stanford Research Systems SR785, Руководство по эксплуатации и программированию

Страница: 101 / 546

Views 2-21
SR785 Dynamic Signal Analyzer
Views
Each measurement has an associated view. A view is a way of looking at the complex
measurement data.
Log Magnitude
Log magnitude view graphs the log of the magnitude of the measurement data. The
magnitude is
√
(x
2
+ y
2
) where x is the real part and y is the imaginary part. The
appearance of a display showing the Log Magnitude view depends on the setting of the
<dB Units> softkey. If <dB Units> are on, the graph is shown plotted with a Y axis
scaled linearly in dBs. If <dB Units> are off, the Y axis is shown scaled logarithmically
in the units of the measurement.
Linear Magnitude
Linear magnitude view graphs the magnitude of the measurement data. The magnitude is
√
(x
2
+ y
2
) where x is the real part and y is the imaginary part. The Y axis of the display is
linear in scaling.
Magnitude
2
Magnitude
2
view graphs the magnitude squared of the measurement data. The magnitude
squared is (x
2
+ y
2
) where x is the real part and y is the imaginary part. The Y axis of the
display is linear in scaling.
Real Part
Real Part view graphs the real part of the measurement data. The Y axis of the display is
linear in scaling.
Imaginary Part
Imag Part view graphs the imaginary part of the measurement data. The Y axis of the
display is linear in scaling.
Real measurement data, such as baseband time record, have zero imaginary part. This
view is zero for all points.
Imaginary data arises from the multiplication of the input time data by sine and cosine
(heterodyne). Signals in phase with cosine result in real data, signals in phase with sine
result in imaginary data. The real and imaginary parts represent data 90 degrees out of
phase.
Phase
Phase view graphs the phase of the measurement data. The phase is a four-quadrant
quantity defined as
θ
= arctan(y/x) where y is the imaginary part and x is the real part
and y is positive. If y is negative, the phase is negated. Phase is graphed linearly from -
180 (-
π
) to +180 (
π
) degrees (radians). To show unwrapped phase, choose the
Unwrapped Phase view.
Real measurement data, such as baseband time record, have zero imaginary part. The
phase is zero for all points.