Agilent Technologies 54621A, 54621D, 24A, 42A, 22A, 41A Smoothing # Avgs=1 or High-resolution mode

Making Measurements

To reduce the random noise on a signal

Smoothing (# Avgs=1) or High-resolution mode

The term smoothing is an oversampling technique used when the digitizer sampling rate is faster than the rate at that samples are being stored into acquisition memory. The sample rate for the 54620-series is 200 MSa/s for single channel or 100 MSa/s with channel pairs 1 and 2, 3 and 4, or pod 1 and pod 2 running. The sample rate for the 54640-series is 2 GSa/s for single channel or 1 GSa/s with channel pairs 1 and 2

For example, if the scope is sampling at 200 MSa/s, yet storing the samples at 1 MSa/s, it needs to store only 1 out of every 200 samples. When smoothing is used, the slower the sweep speed, the greater the number of samples that are averaged together for each display point. This tends to reduce random noise on the input signal, which produces a smoother trace on the screen.

If you cannot acquire multiple triggers, you can still reduce noise and increase resolution at slower sweep speeds by setting # Avgs to 1.

54620-series	54640-series	Bits of resolution
Sweep speed	Sweep speed	(# Avgs=1)
≤ 2 us/div	200 ns/div	8
5 us/div	1 us/div	9
20 us/div	5 us/div	10
100 us/div	20 us/div	11
500 us/div	100 us/div	12

5-9