HP 8753E Press ~~~~~~ MarkerFctn‘~~~~~~~, Bandpass or band reject shape on the measurement trace

Searching for a Bandwidth

The analyzer can automatically calculate and display the -3 dB bandwidth (BW:), center frequency (CENT:), Q, and loss of the device under test at the center frequency. (Q stands for “quality factor,” defined as the ratio of a circuit’s resonant frequency to its bandwidth.) These values are shown in the marker data readout.

1. Press m and turn the front panel knob, or enter a value from the front panel keypad to

place the marker at the center of the filter passband.
.,..,;	: ,, ,.	:: ..%.. .i/. ,..

3. Press ~:~~~~~ (MarkerFctn)‘~~~~~~~		to access the marker search menu.
* ..*..	,/,,,,.,..........., s.....,......,,,,... .:::.. :::... .....i.	~..:........;../

3. Press ~%&XRl&fl!& to calculate the center stimulus value, bandwidth, and the Q of a
T. i	.:	..i i ‘,,
:,.,................i/.i

bandpass or band reject shape on the measurement trace.

4. If you want to change the amplitude value (default is -3 dl3) that defines the passband or
	_	i “’
rejectband, press ~~~~~~~. and enter tie new value from *e front panel keypad*
i................../	.:::::..	........................i

Figure Z-27. Example of Searching for a Bandwidth Using Markers

Tracking the Amplitude that You Are Searching

1. Set up an amplitude search by following one of the previous procedures in “To Search for a

Specific Amplitude. n	......:t :<::. ..c,:;, :e,	:.~ .~,.~.~.~.~,~,~,~,~,~	;,.,;...
“::IxE:5~~~~ .‘?g .:Fj.::<~/:.::		,.. .,		to track the specified amplitude search
2. Press (MarkerFctn) ~~~~~~~~ ,~~~~~~~~~~
:.i..::: ...A.;::..:::: :............A...a:............ii>u..;..>..A...;:.......:.::..:.__.v~::..::: ,... . .li....A..L..i			A.....~;;...~..~::.:::..:..l.i :..

with every new trace and put the active marker on that point.

When tracking is not activated, the analyzer IInds the specified amplitude on the current sweep and the marker remains at same stimulus value, regardless of changes in the trace response value with subsequent sweeps.

Making Measurements 236