Fluke PM3370B user manual Analog and Digital Modes, Signal Criteria Analog Mode Digital Mode

HOW TO USE THE INSTRUMENT 4 - 9

4.3 ANALOG AND DIGITAL MODES

ANALOG

This instrument is a combination of an analog real-time oscilloscope and a digital storage oscilloscope, which offers a variety of additional features. The combination of analog and digital modes in one instrument gives you the advantages of both modes.

In the ANALOG MODE the signal is directly written on the screen. The result is the "traditional" real-time signal representation. Because of the high update rate and infinite resolution, this image gives signal details that are visible only on true analog oscilloscopes.

In the DIGITAL MODE the input signal is sampled. These samples are stored in memory so that mathematics, calculated measurements, printing, and other memory functions can be performed on the trace.

You can use the yellow ANALOG push button to switch from the analog mode to the digital mode and back at any time. The signal acquisition and display functions of both operating modes are very similar. However, the nature of the signals you are using may determine which operating mode you prefer to use. For more information, refer to the following table:

SIGNAL CRITERIA	ANALOG MODE	DIGITAL MODE
Repetitive signals of	Usable	Usable
30 Hz and higher
Repetitive signals	Causes display	Preferred
below 30 Hz	flickering
Single events	Display for	Can capture and
	duration of	display for long
	the event	term
Repetitive signals that	Preferred	May cause aliasing.
are amplitude modulated		Use Peak detect or
		Envelope mode
Repetitive signals that	Preferred	May cause aliasing.
are modulated in frequency		Use Envelope mode.
Long serial data streams	Preferred when	When using delayed
	Delayed sweep	sweep to observe
	is not used.	details, Digital mode
		provides better
		light output.