3.Substitute a thru for the device and perform a response calibration by pressing: &g ~:~~~~~~~~; ~~~~~~~,, ;@Ji@.

4.Reconnect your test device.

5.To better view the measurement trace, press:

,,....

(7):&q#j : <&&$

Notice that in Figure 2-34 the SAW filter under test has considerable phase shift within only a 2 MHz span. Other filters may require a wider frequency span to see the effects of phase shift.

The linearly changing phase is due to the device’s electrical length. You can measure this changing phase by adding electrical length (electrical delay) to compensate for it.

Figure 2-34. Linearly changing Phase

6.To place a marker at the center of the band, press:

e and turn the front panel knob, or enter a value from the front panel keypad.

7.To activate the electrical delay function, press:

(Markeri$$&@,$&;TTFa”, .;>..;;;;.MARKERi ..>;;;;;;DELAY.;/i/.*

~~~~~~~,

This function calculates and adds in the appropriate electrical delay by taking a &lo% span about the marker, measuring the A4, and computing the delay as the negative of AdlAfrequency.

Making Measurements 241

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HP 8753E manual Linearly changing Phase