R&S ESCI Analyzer - Traces
1166.6004.12 4.111 E-1
Selection of Detector
The detectors of the R&S ESCI are implemented as pure digital devices. The detectors available are the
peak detectors which determine the maximum and/or the minimum value from a number of samples,
the rms detector which measures the power within a pixel, the average, the quasipeak and the sample
detector. The sample detector routes through the sampled data without any modification or performs a
data reduction by suppressing measured values that cannot be displayed.
The peak detectors compare the current level value with the maximum or minimum level from the
previously sampled data. When the number of samples defined by the instrument setting is reached, the
samples are combined in displayable pixels. Each of the 501 pixels of the display thus represents 1/501
of the sweep range and contains all single measurements (frequency samples) in this subrange in
compressed form. For each trace display mode an optimized detector is selected automatically. Since
peak detectors and sample detector are connected in parallel, a single sweep is sufficient for collecting
all detector values for 3 traces.
Peak detectors
(
MAX PEAK and MIN PEAK)
Peak detectors are implemented by digital comparators. They
determine the largest of all positive (max peak) or the smallest of
all negative (min peak) peak values of the levels measured at the
individual frequencies which are displayed in one of the 501
pixels. This procedure is repeated for each pixel so that for wide
frequency spans and despite the limited resolution of the display a
large number of measurements can be taken into consideration
for the display of the spectrum.
Autopeak detector The
AUTOPEAK detector combines the two peak detectors. The
max peak detector and the min peak detector simultaneously
determine the maximum and the minimum level within a displayed
testpoint and display it as a single measured value. The maximum
and minimum levels within a frequency point are connected by a
vertical line.
Sample detector The
SAMPLE detector routes through the sampled data without
any further evaluation and either displays them directly or, for
reasons of speed in case of short sweep times, first writes them
into a memory and processes them subsequently.
There is no data reduction, ie no summing up of measured values
of neighbouring frequencies or time samples. If during a
frequency sweep more measured values are obtained than can
be displayed, measured values will be lost. This means that
discrete signals might be lost.
The sample detector therefore can only be recommended for a
span-to-resolution bandwidth ratio of up to approx. 250 in order to
ensure that no signal will be suppressed (example: span 1 MHz, -
> min. bandwidth 5 kHz).
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