Using an Oscilloscope`s Memory Depth

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Using an
Oscilloscope’s
Memory Depth
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Long Memory Storage with Rigol Oscilloscopes
Some Digital scopes offer the capability of capturing waveforms in Long
Memory mode. Utilizing the long memory, Rigol scopes can capture
complex signals in great detail over extended time periods. This allows an
observer to examine high frequency effects within the captured waveform.
How to use Long Memory Mode on the DS1000D/E Series scopes?
 Enter the Acquire menu by pressing the Acquire button
 Set the Memory Depth field to Long Memory
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Sampling rate and Long Memory:
Using the DS1000E and DS1000D Series Rigol digital scopes, users can
access the long memory mode to get up to 512Kpts in dual channel mode
and up to 1Mpts in single channel mode. In comparison, standard memory
depth for oscilloscopes range from 1000pts - 16Kpts.
This high sampling rate is a big advantage when observing signals
where the application requires capturing a longer waveform, but also needs
to confirm higher frequency components within the signal.
The best way to visualize these higher frequency components is to use
the zoom feature. By pushing the Horizontal knob, you can enter zoom
mode. In this screen shot you see a 0.5 second waveform in yellow across
the top. In the lower section we have zoomed in to 10 usec/division. Since
we are sampling in normal mode you can see the distance between two data
points. A straight line connects data points and you can see where the signal
rises between samples and is clearly being linearly interpolated. On the
DS1000D/E Series scopes this normal mode operation has 16 Kpts per wave.
Since the overall wave is set to 50 msec/div the 10 divisions across the
screen make the wave 0.5 seconds. 16 Kpts spread across 0.5 seconds means
there is one sample approximately every 32 usec. This is confirmed by the
screen shot.
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Using the method above to switch the scope to deep memory mode
we can see the increased sampling rate below. In this image the increased
data rate is seen by observing the real shape of the rise time. Now with the
increased sampling we have 1 million points over 0.5 seconds for one sample
about every 500 nsec.
The table below shows the memory capabilities of all Rigol
Oscilloscope series.
Series
Memory Depth
DS1000E
1 Mpts
DS1000D
1 Mpts
DS1000CA
10 Kpts
DS1000B
16 Kpts
DS6000
140 Mpts
*capabilities above in 1 channel mode, within maximum sampling speeds
In conclusion, memory depth is an important feature to consider when
selecting an oscilloscope because high frequency components can be
important to the analysis, triggering, and monitoring of signals. Memory
RIGOL TECHNOLOGIES USA INC
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depth combined with maximum sampling rates, waveform acquisition rates,
and an oscilloscope’s display quality all impact the overall ease of capturing
and analyzing data with your oscilloscope.
For more information or questions contact us directly at:
Rigol Technologies USA
7401 First Place
Suite N
Oakwood Village, OH 44146
You can reach us directly at:
(440) 232-4488
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info@rigol.com
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