Technical data

Measurement Setup 15
Agilent N8201A Performance Downconverter Synthetic Instrument Module, 250 kHz to 26.5 GHz 373
Peak
For each interval (bucket) in the trace, Peak detection displays the highest amplitude within
the interval. Peak detection is used for CW measurements and some pulsed-RF
measurements. For swept analysis, peak detection basically obtains the maximum video
signal between the end of the last bucket and the start of the next one. Gain is increased to
compensate for the effects of faster sweep rates, to keep the displayed value accurate. For
FFT analysis, the highest spectral amplitude is displayed, even if that peak amplitude falls
between samples of the spectrum computed in the FFT process.
When Peak is selected, Peak appears on the left side of the display.
Key Path: Meas Setup, Range Table, Detector 1 or Detector 2
State Saved: Saved in Instrument State.
Remote Command: See “Detector 2" on page 371.
Sample
The sample detector displays the instantaneous level of the signal at the center of the
interval (bucket) represented by each trace point.
Sample detection is primarily used to display noise or noise-like signals.
Sample detection is not best for 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, 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 to do so would cause errors in the response to noise.
When Sample is selected, Samp appears on the left side of the display.
Key Path: Meas Setup, Range Table, Detector 1 or Detector 2
State Saved: Saved in Instrument State.
Remote Command: See “Detector 2" on page 371.
Negative Peak
For each interval (bucket) in the trace, Negative Peak detection displays the lowest sample
within the interval.
When Negative Peak is selected, NPk appears on the left side of the display.
Key Path: Meas Setup, Range Table, Detector 1 or Detector 2