Agilent Technologies U9072A cdma-2000

1316

Trace/Detector

highest amplitude across the frequency width of a bucket is displayed, even if that peak amplitude falls

between samples of the spectrum computed in the FFT process.

Sample

The sample detector displays the instantaneous level of the signal at the center of the bucket (interval)

represented by each trace point.

Sample detection is good for displaying noise or noise-like signals.

Sample detection is not the best for making amplitude measurements of CW-like signals for two reasons.

First, the peak response to a signal can occur between samples. So unless the Span to RBW ratio is lower

than usual, then the highest sample can be well below the peak signal amplitude. Second, for the high

sweep rates normally used, the peak response of the RBW filters is up to –0.5 dB. This sweeping error is

compensated when using the peak and normal detectors by changing the overall gain. But the gain is not

changed when in the sample detector, because doing so would cause errors in the response to noise.

Instead, the auto-couple rules for sweep time are modified to give slower sweeps.

Negative Peak

For each bucket (interval) in the trace, Negative Peak detection displays the lowest sample within the

Key Path Trace/Det, Detector

Example DET:TRAC2 POS sets the detector to peak for trace 2.

Couplings Selecting a specific detector type turns “Auto” to false for this trace (manual).

Selecting a detector for a trace (pressing the key or sending a

[:SENS]:DET:TRAC command) puts Update On and Display On for that

trace, even if that detector was already selected. Note that the legacy

command [:SENS]:DET[:FUNC] does NOT exhibit this behavior.

Selecting a detector, whether by pressing the key or sending the equivalent

SCPI command, will turn trace math to Off for the selected/specified trace.

Initial S/W Revision Prior to A.02.00