ADInstruments AD8000 Series Instruction Manual page 74

AD8000 Series Spectrum Analyzer Instruction
Manual
(2) Positive-Peak
When the sweep time is long enough, the positive peak detection mode
could get the largest envelop of the signal. Sometimes, when the
modulation signal is measured, this mode could eliminate the modulation
interference, and get the stable ampliltude of the signal. The enough sweep
time does not means that 'UNCAL' does not show up. The time should be
longer, since the calculation of 'UNCAL' is gotten according to sample
detection mode. It usually needs 1~3 times of the minimum time.
With the sample detection mode and a relative wide span, the RBW could
not always cover all signals. Presume the current span is 16MHz, and RBW
is 1Mhz. if there are 16 points on the screen, it would shows as below:
60
Fig. 3-33 Positive Peak Detection
Fig. 3-34 RBW Detection Wave Envelop