Making a Basic Measurement

Viewing a Signal

Improving Frequency Accuracy

10.While not all of the zeros following the decimal in the active function block are significant, the numbers after the decimal in the marker annotation (upper-right corner of screen) are significant. To increase the accuracy of the frequency reading in the marker annotation, turn on the frequency count function.

a.Press Mkr Fctn.

•The Marker Fctn softkeys appear.

b.Press Marker Count.

•The Marker Count softkeys appear.

11.Note softkey Marker Count On Off. If Off is underlined, press the softkey to toggle marker count on.

As shown in Figure 3-5:

•The marker annotation changes from Mkr1 to Cntr1.

•The displayed resolution in the marker annotation improves.

NOTE

When you use the frequency count function, if the ratio of the resolution

 

bandwidth to the span is less than 0.002, the following message

 

appears on the display: Freq Count: Reduce Span/RBW ratio

 

This indicates that the resolution bandwidth is too narrow.

 

 

12.Press Marker ➞ , Mkr ➞ CF to move the 10 MHz peak to the center of the display.

Valid Marker Count Range

13.Move the marker down the skirt of the 10 MHz peak. Note that although the readout in the active function changes, as long as the marker is at least 26 dB above the noise, the counted value (upper-right corner of display) does not change (see Figure 3-6). For an accurate count, the marker does not have to be at the exact peak.

NOTE

Marker count functions properly only on CW signals or discrete peaks.

 

For a valid reading, the marker must be ≥ 26 dB above the noise.

 

 

14.Press BW/Avg, Res BW, then enter a new value. This action makes the resolution bandwidth the active function and allows you to experiment with different resolution bandwidth (RBW) values.

15.Press Marker, Off to turn the marker off.

NOTE

After properly setting the analyzer to display your signal, you can save

 

the settings as either a user preset (press System, Power On/Preset, Save

 

User Preset), or a file (see “Saving a File” on page 48).

 

 

Chapter 3

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HP E4446A, E4448A, E4440A, E4445A, E4443A manual Improving Frequency Accuracy, Valid Marker Count Range
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E4443A, E4448A, E4445A, E4446A, E4440A specifications

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