Operators Manual Owner manual

HDO6000 High Definition Oscilloscope

Enhanced Resolution

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:

l On single-shot acquisitions, or where the data record is slowly repetitive (cases where you cannot

use averaging).

l To reduce noise on noticeably noisy signals when you do not need to perform noise measurements.

l When performing high-precision voltage measurements (e.g., zooming with high vertical gain).

ERes can be applied as a form of Pre-Processing, or as a Math function.

Set Up Enhanced Resolution (ERes)

To quickly set up ERes, open the Channel setup dialog and in the Pre-Processing section select a Noise

Filter (ERes) bit size .

To apply ERes as a Math function:

1. Follow the usual steps to set up a math function, selecting ERes from the Filter submenu.

2. Touch the Trace On checkbox.

3. Touch the ERes right-hand dialog tab , then touch bits and make a selection from the pop-up menu.

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 your signal is single-

shot or repetitive. The signal-to-noise ratio (SNR) improvement you gain is dependent 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. The parameters of the six filters are given in the following table.

Resolution increased by

-3 dB Bandwidth

(x Nyquist)

Filter Length

(Samples)

0.5 0.5 2

1.0 0.241 5

1.5 0.121 10

2.0 0.058 24

2.5 0.029 51

3.0 0.016 117

With low-pass filters, the actual SNR increase obtained in any particular situation depends on the power

spectral density of the noise on the signal.

922499 Rev B