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Gentlemen this is about the Smooth Feature on the DMM's

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Kiriakos-GR:
People I need lots of enlightenment about the  Smooth Feature - Function. ( what ever you called it .)

In theory :
When the input signal changes rapidly, “smoothing”
provides a steadier reading on the display.

Or..

Smooth is used to smoothen the refresh rate of the readings
in order to reduce the impact of unexpected noise and to
help you achieve a stable reading

Ok, so far so good, the point is how much is enough ?

The advanced versions of the Fluke DMM, they had an fixed refresh about the Smooth Feature.
And the latest Agilent U1272A offers the potential of manually adjust. 

And the key question is: How slow it called as very slow ?
Fluke does not say, how many milliseconds delay added, when their  “smoothing” gets enabled.

From the other hand, the Agilent U1272A it is so extremely fast,
that definitely needs active “smoothing” in some types of measurements.
In their User Manual they speak about adjustment from (0001 to 9999) but they do not say what those are ?
Are they milliseconds ?

9999 Milliseconds = 9.999 Seconds

EEVblog:

--- Quote from: Kiriakos-GR on July 05, 2011, 10:04:14 pm ---In their User Manual they speak about adjustment from (0001 to 9999) but they do not say what those are ?
Are they milliseconds ?

--- End quote ---

Averaging is almost always quoted in number of samples, most likely a running average in this case of a smoothing feature on multimeters.

Dave.

Kiriakos-GR:
ok I am trying hard here so to get the point or to translate it in something understandable.

Questions : With out “smoothing” , the DMM operates at the Max sample rate that could be 9999 ?
And so if I set less samples per second, I am slowing it down ?

alm:
It's likely using a windowed moving average, which calculates the average over the last n points, but resets the sample population (restart from scratch) if the new value is outside the window (eg. avg +/- 10%). This is designed to smooth small fluctuations, but leave transient response to major changes in tact. Averaging over a larger number of samples will slow down response to gradual changes.

EEVblog:

--- Quote from: Kiriakos-GR on July 06, 2011, 12:50:15 am ---ok I am trying hard here so to get the point or to translate it in something understandable.

Questions : With out “smoothing” , the DMM operates at the Max sample rate that could be 9999 ?
And so if I set less samples per second, I am slowing it down ?

--- End quote ---

The ADC in the DMM always operates at the max sample rate, and the display update speed (say 4 times/sec) likely remains the same too.
The difference is what value is displayed.
Without smoothing, the ADC just send the value directly to the display each time.
But with smoothing set to say 4, the processor calculates the average of the last 4 readings and then displays that. Perhaps with "windowed" method like ALM explained which is able to reset the average count.

Dave.

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