SRS Labs SR850 - Manual (Page 33)

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Press <Cursor Seek> to select Min.
Use the knob to read the frequencies of the
notch filter zeroes or minimums.
13. Press [DISPLAY/SCALE]
Press <Type/Trace> to highlight the Trace
number again.
Use the knob to select Trace 1.
Use the knob to select Trace 2.
Use the knob to select Trace 4.
Press [AUTO SCALE].
14. Press [PAUSE/RESET]
15. Press {START/CONT]
quency of each point is displayed in the cursor
coordinate display.
The graph shows all 3200 data points at once.
Since the screen resolution only has 640 pixels
across, each X-axis value must represent multiple
data points. The cursor reads the Max, Min or
Mean of the data points graphed at each X-axis
position.
To read the notch filter minimum frequencies,
select Min.
The cursor displays the frequency and trace value
of the smallest data point graphed at each horizon-
tal X-axis position.
Show the Display and Scale menu again.
The SR850 can store up to 4 traces simultaneous-
ly. In the default configuration, all 4 traces are
stored. Let's take a look at the other traces.
Trace 1 is X. This corresponds to the real part of
the filter response.
Trace 2 is Y. This corresponds to the quadrature
part of the filter response (or derivative of X).
Trace 4 is
θ
. This is the phase response of the fil-
ters. The phase approaches 180° at the exact filter
notch frequencies and approaches zero at fre-
quencies far from the notches. In many experi-
ments, the phase (or quadrature) measurements
yield a far more exact measure of the actual reso-
nant or peak frequency than R.
Pressing the [PAUSE/RESET] key while DONE
will reset the scan and sweep. The stored data is
lost and the scan indicator shows STOP again.
Swept parameters (frequency in this case) return
to their start values and the graph is blanked.
Let's take the data again, this time while displaying
the chart to show the scan data in progress.
The data scrolls in from the right. New points are
added at the right edge and the old points move to
the left. This is a strip chart type of graph.
The buffers can be configured for a single scan
(1 Shot) as in this measurement, or continuous
Scans and Sweeps