Operators Manual Owner manual

HDO6000 High Definition Oscilloscope

Graph Function

To reduce noise: The example at left shows enhanced resolution of a noisy signal.

The original trace (left top) has been processed by a 2-bit enhanced resolution filter.

The result (left bottom) shows a smooth trace, where most of the noise has been

eliminated.

NOTE: While enhanced resolution can only improve the resolution of a trace, it cannot improve the

accuracy or linearity of the original quantization. The pass-band causes signal attenuation for signals

near the cut-off frequency. The highest frequencies passed may be slightly attenuated. Perform the

filtering on finite record lengths. Data is lost at the start and end of the waveform and the trace ends up

slightly shorter after filtering. The number of samples lost is exactly equal to the length of the impulse

response of the filter used: between 2 and 117 samples. Normally this loss (just 0.2 % of a 50,000 point

trace) is not noticed. However, you might filter a record so short that no data is output. In that case,

however, the instrument would not allow you to use the ERes feature.

Averaging Waveforms

Summed Averaging

Summed Averaging is the repeated addition, with equal weight, of successive source waveform records. If

a stable trigger is available, the resulting average has a random noise component lower than that of a

single-shot record. Whenever the maximum number of sweeps is reached, the averaging process stops.

In Summed averaging, you specify the number of acquisitions to be averaged. The averaged data is

updated at regular intervals and presented on the screen.

An even larger number of records can be accumulated simply by changing the number in the dialog.

However, the other parameters must be left unchanged or a new averaging calculation will be started. You

can pause the averaging by changing the trigger mode from NORM/AUTO to STOP. The instrument

resumes averaging when you change the trigger mode back to NORM/AUTO.

You can reset the accumulated average by pushing the CLEAR SWEEPS button or by changing an

acquisition parameter such as input gain, offset, coupling, trigger condition, timebase, or bandwidth limit.

The number of current averaged waveforms of the function, or its zoom, is shown in the acquisition status

dialog. When summed averaging is performed, the display is updated at a reduced rate to increase the

averaging speed (points and events per second).

Continuous Averaging

NOTE: Continuous Averaging may be set up from either the Channel dialog under Pre-Processing, or as a

Math function.

Continuous Averaging, the default setting, is the repeated addition, with unequal weight, of successive

source waveforms. It is particularly useful for reducing noise on signals that drift very slowly in time or

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