Eres Function - Teledyne HDO9000 Operator's Manual

HDO9000 High Definition Oscilloscopes Operator's Manual

ERes Function

ERes (Enhanced Resolution) filtering increases vertical resolution, allowing you to distinguish closely
spaced voltage levels. The instrument's ERes function is similar to smoothing the signal with a
simple, moving-average filter. However, it is more efficient concerning bandwidth and pass-band
filtering.
Use ERes:
On single-shot acquisitions, or where the data record is slowly repetitive (cases where you
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cannot use averaging).
To reduce noise on noticeably noisy signals when you do not need to perform noise
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measurements.
When performing high-precision voltage measurements (e.g., zooming with high vertical gain).
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Setting Up ERes
To apply ERes as a Math function:
1. Follow the usual steps to
2. Touch the Trace On checkbox.
3. On the Eres subdialog, then touch bits and make a selection from the pop-up menu.
Tip: To quickly set up ERes as a pre-processing function, access the channel setup dialog
(Cx) and select a Noise Filter (ERes) bit size.
How the Instrument Enhances Resolution
The instrument's enhanced resolution feature improves vertical resolution by a fixed amount for each
filter. This real increase in resolution occurs whether or not the signal is noisy, or whether it is single-
shot or repetitive. The signal-to-noise ratio (SNR) improvement depends on the form of the noise in
the original signal. The enhanced resolution filtering decreases the bandwidth of the signal, filtering
out some of the noise.
The instrument's constant phase finite impulse response (FIR) filters provide fast computation,
excellent step response in 0.5 bit steps, and minimum bandwidth reduction for resolution
improvements of between 0.5 and 3 bits. Each step corresponds to a bandwidth reduction factor of
two, allowing easy control of the bandwidth resolution trade-off.
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set up a math function, selecting Eres from the Filter submenu.