Specifications

The following picture demonstrates the ability of the scope to average out random noise:

Figure 27

The signal at A was a 200 mV square wave with substantial random noise. At B, the signal has been

averaged 16 times and the noise is substantially reduced. At C, 256 waveforms have been averaged

and the noise is essentially gone.

Averaging can only be used on periodic signals, but since these are often measured, averaging finds

frequent use in day-to-day oscilloscope measurements.

Peak detection

Measuring narrow-width pulses using a slow sweep speed can be challenging with an analog

oscilloscope, even if the scope can trigger on the pulses. A digital scope can use peak detect mode to

show these narrow pulses. Peak detection shows the highest and lowest values from multiple triggers

and thus uses the techniques of equivalent-time sampling. The advantage of peak detection is that it

can show these narrow pulses at slow sweep speeds.

An example of where peak detection is useful is shown in the following picture:

Figure 28

The waveform was a 100 Hz pulse stream with 10 ns wide pulses (this is a 0.0001% duty cycle pulse

train). At A, normal acquisition mode was used and the pulses are not visible, yet the scope had

triggered. At B, peak detection acquisition mode has been turned on and the pulses become visible. An

analog scope would have a difficult time displaying these pulses.

Copying/reprinting/republishing without express written consent prohibited.