Fluke PM3370B user manual Peak Detection

FUNCTION REFERENCE 5 - 51

PEAK DETECTION

Description:

This function is available only in the digital mode.

In the acquisition system of a Digital Storage Oscilloscope, the sample distance is determined by the time base speed. At higher time base speeds, the distance between the samples is short; at lower time base speeds, the sample distance is longer.

To capture high frequency signals, or signal details of short duration, a high time base speed is usually selected. A high time base speed captures a time ‘window’ that is usually equivalent to the length of the screen. So at higher time base speeds, the time ‘window’ is shorter than at lower time base speeds.

Some applications require the time ‘window’ to be long. This is then achieved by selecting a slow time base speed, to fit the requirement. But at lower time base speeds, the time distance between the actual samples increases. The result is, that signal details shorter than the sample distance will be missed.

The peak detection mode allows the Analog to Digital Convertors (ADC) to operate at their highest speed, even when a lower time base speed has been selected. The result is that, even at lower time base speeds, the maximum or minimum peaks of the signals are placed in memory and displayed. This technique is referred to as oversampling.

Using peak detection (PEAK DET) allows you to capture peak values of the input signal which may otherwise occur between the samples. PEAK DET operates on repetitive signals as well as on signals taken in a single acquisition.

The shortest events (or ‘glitches’) that can be captured are 5 ns in the single channel mode and 10 ns in the dual channel mode. Selection of peak detection is made from the ACQUIRE menu.

The following is an overview of peak detection possibilities:

Mode of use	Description	Peak detection speed
one channel	any channel	5 ns
two channels	Ch1 & Ch2 or Ch3 & Ch4	10 ns
three channels	ALT mode	10 ns
	CHOP mode	not applicable
four channels	ALT mode	10 ns
	CHOP mode	not applicable