User manual

Acquisition and Setup
R&S
®
RTO
33User Manual 1316.0827.02 ─ 06
"Equivalent
time"
This method requires repetitive, stable signals and is not suitable for
random and non-repetitive signals. It is used to capture fast signals
whose frequency components are higher than the "ADC sample rate".
Equivalent-time sampling constructs a picture of a repetitive signal by
capturing a little bit of information from each repetition. Each sample is
taken with some time difference after the trigger, and the time difference
varies with each repetition of the signal. After a number of acquisitions,
the oscilloscope builds the waveform from the sampled points.
The R&S RTO uses the sequential equivalent-time sampling method.
When a trigger occurs, a sample is taken after a very short delay time.
At the next trigger, this delay time is incremented by a precisely defined
Δt, and the next sample is taken. This process is repeated until the
waveform is complete. Sequential equivalent-time sampling provides
very good time resolution and accuracy.
Equivalent-time sampling is not available, if digital channels are active
(requires option RTO-B1, MSO).
SCPI command:
ACQuire:MODE on page 433
Interpolation mode
Selects the interpolation method if "Interpolated time" is set for enhancement.
"Linear"
Two adjacent ADC sample points are connected by a straight line, the
interpolated points are located on the line. You see a polygonal wave-
form similar to the real signal, and also the ADC sample points as ver-
texes.
"sin (x)/x"
Two adjacent ADC sample points are connected by a sin(x)/x curve,
and also the adjoining sample points are considered by this curve. The
interpolated points are located on the resulting curve. This interpolation
method is very precise and shows the best signal curve.
"Sample/Hold"
The ADC sample points are displayed like a histogram. For each sam-
ple interval, the voltage is taken from the sample point and considered
as constant, and the intervals are connected with vertical lines. Thus,
you see the discrete values of the ADC - the actually measured sam-
ples.
SCPI command:
ACQuire:INTerpolate on page 433
Enable Wfm
Activates or deactivates the individual waveforms of the selected channel.
For each channel, up to three waveforms can be shown and analyzed. The decimation
mode and the trace arithmetic are specific for each waveform. So you can analyze several
aspects of the signal: For example, waveform1 shows the peaks, and waveform2 shows
the average of the signal.
SCPI command:
CHANnel<m>[:WAVeform<n>][:STATe] on page 433
Reference for Acquisition and Setup