Specifications

Chapter 4 33
Improving Frequency Resolution and Accuracy
Using a Frequency Counter to Improve Frequency Resolution and Accuracy
Improving Frequency Resolution
and Accuracy
Figure 4-1 Using Marker Counter (ESA Display)
Step 6. Change counter resolution:
ESA frequency-counter resolution can be set from 1 Hz to 100 kHz by
pressing
Freq Count, Resolution.
PSA frequency-counter resolution is fixed at 0.001 Hz for 2 ms and
longer gate times. Longer gate times allow for greater averaging of
signals whose frequency is "noisy", at the expense of throughput.
NOTE For PSA, if the Gate Time (under the Marker Count menu) is an integer
multiple of the length of a power-line cycle (20 ms for 50 Hz power,
16.67 ms for 60 Hz power), the counter rejects incidental modulation at
the power line rate. The shortest
Gate Time that rejects both 50 and 60
Hz modulation is 100 ms (100 ms is the default
Gate Time setting when
set to Auto).
Step 7. The marker counter remains on until turned off. Turn off the marker
counter:
(ESA) Press
Freq Count, Marker Count (Off). Or Press Marker, Off.
(PSA) Press
Marker Fctn, Marker Count, Marker Count (Off). Or Press
Marker, Off.
NOTE When using the built-in frequency counter function with the ESA, if the
ratio of the resolution bandwidth to the span is too small (less than or
equal to 0.002), the Marker Count: Widen Res BW message appears on
the display. It indicates that the resolution bandwidth is too narrow.