Loading ...
Loading ...
Loading ...
Waveform Setup
R&S
®
RTB2000
51User Manual 1333.1611.02 ─ 03
Acquire Mode
Defines how the waveform is built from the captured samples. There are two general
methods to build the waveform record: sample decimation and waveform arithmetic.
Sample decimation reduces the data stream of the ADC to a stream of waveform
points with lower sample rate and a less precise time resolution. The R&S RTB2000
uses decimation, if the waveform sample rate is less than the ADC sample rate. The
acquisition modes "Peak Detect" and "High Resolution" are decimation methods.
Waveform arithmetic builds the resulting waveform from several consecutive acquisi-
tions of the signal. The acquisition modes "Average" and "Envelope" are arithmetic
methods.
"Sample"
Usually, most signals are displayed optimally with this acquisition
mode but very short glitches might remain undiscovered by this
method. If the sample rate of the waveform is less than the ADC sam-
ple rate, the instrument reduces the number of samples: one of n
samples in a sample interval is recorded as waveform point, the other
samples are discarded (decimation). Conversely, if the sample rate of
the waveform is higher than the ADC sample rate, the instrument
adds waveform points to the captured samples using an interpolation
method.
"Peak Detect"
The minimum and the maximum of n samples are recorded as wave-
form points, the other samples are discarded. Thus the instrument
can detect fast signal peaks at slow time scale settings that would be
missed with other acquisition modes.
"High Resolu-
tion"
The average of n captured sample points is recorded as one wave-
form sample. Averaging reduces the noise, the result is a more pre-
cise waveform with higher vertical resolution.
"Average"
The average is calculated from the data of the current acquisition and
a number of consecutive acquisitions before. The method reduces
random noise. It requires a stable, triggered and repetitive signal.
The number of acquisitions for average calculation is defined with
"No. of Averages" on page 52.
"Envelope"
Each acquisition is done in sample decimation mode, and the mini-
mum and maximum values over some consecutive acquisitions build
the envelope. The resulting diagram shows two envelope waveforms
below and above the normal waveform: the minimums (floor) and
maximums (roof), representing the borders in which the signal
occurs. this method is useful, for example, if the waveform is noisy
but the noise is not relevant for the measurement.
"Enve-
lope + PD"
Each acquisition is done in peak detect decimation mode, and the
most extreme values of all consecutive acquisitions build the enve-
lope. This method is more precise than "Envelope".
Remote command:
ACQuire:TYPE on page 262
CHANnel<m>:ARIThmetics on page 262
CHANnel<m>:TYPE on page 261
ACQuire:PEAKdetect on page 263
ACQuire:HRESolution on page 263
Acquisition Setup
Loading ...
Loading ...
Loading ...