Realtime Sampling Option - Agilent Technologies InfiniiVision 5000 Series User Manual

Realtime Sampling Option

InfiniiVision Oscilloscopes User's Guide
Realtime sampling specifies that the oscilloscope produce the waveform display from
samples collected during one trigger event (that is, one acquisition).
Use Realtime sampling to capture infrequent triggers, unstable triggers, or complex
changing waveforms, such as eye diagrams.
Realtime sampling can be turned on in Normal, Peak Detect, or High Resolution
acquisition modes. It cannot be turned on when the acquisition mode is Averaging.
When Realtime sampling is on (as in the default setup):
• When less than 1000 samples can be collected in the time spanned by the screen, a
sophisticated reconstruction filter is used to fill in and enhance the waveform display.
• If you press the [Stop] key, and pan and zoom through the waveform using the
Horizontal and Vertical controls, only the last trigger's acquisition will be displayed.
When Realtime sampling is off:
• The oscilloscope produces the waveform display from samples collected from multiple
acquisitions. In this case, the reconstruction filter is not used.
Realtime Sampling and Oscilloscope Bandwidth
To accurately reproduce a sampled waveform, the sample rate should be at least four
times the highest frequency component of the waveform. If not, it is possible for the
reconstructed waveform to be distorted or aliased. Aliasing is most commonly seen as
jitter on fast edges.
The maximum sample rate for 350 MHz bandwidth oscilloscopes is 2 GSa/s.
The maximum sample rate for 1 GHz and 500 MHz bandwidth oscilloscopes is 4 GSa/s for
a single channel in a channel pair. Channels 1 and 2 constitute a channel pair, and
channels 3 and 4 constitute another channel pair. For example, the sample rate of a
4-channel oscilloscope is 4 GSa/s when channels 1 and 3, 1 and 4, 2 and 3, or 2 and 4 are
on.
Whenever both channels in a channel pair are on, the sample rate for all channels is
halved. For example, when channels 1, 2, and 3 are on, the sample rate for all channels is
2 GSa/s.
When Realtime sampling is on, the bandwidth of the oscilloscope is limited because the
bandwidth of the reconstruction filter is set to f
channels 1 and 2 on has a bandwidth of 500 MHz when Realtime sampling on and 1 GHz
when Realtime sampling is off.
Acquisition Modes
/4. For example, a 610x oscilloscope with
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