Fluke PM3370B user manual Main Timebase Manual + Automatic, 46FUNCTION Reference, VAR ns

Models: PM3370B

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5 - 46FUNCTION REFERENCE

MAIN TIMEBASE

MANUAL + AUTOMATIC

Description:

The Main Timebase (MAIN TB) has a wide range of time/div settings. This enables the display of signals of various frequencies to be displayed with optimum resolution. The time scale is adjusted with the key pair TIME/DIV (VAR). Adjustment can be done in steps or in a continuous range (VAR). Switching between these modes is done by pressing both keys simultaneously. For low frequency signals, the MAIN TB speed must be slow; this is obtained by pressing the ’s’ side of the key pair. For high frequency signals, the ’ns’ side is pressed. Time values of a signal can be determined as described under the ’screen controls and graticule’ function. The AUTO RANGE key activates a continuous automatic adjustment of the TIME/DIV of the main timebase. The result is a display of between 2 and 6 waveform periods on the screen. This functions in digital mode. For more information, refer to the AUTO RANGE function.

If AUTO RANGE is turned on when VAR is active, the timebase is changed in such a way that the trace on display is kept unchanged.

In the digital mode, the timebase speeds are determined by an XTal oscillator. VARiable control of the timebase speeds in digital mode happens in bigger steps than in analog mode

AUTO

RANGE

TIME/DIV

ST6838

9312

Function of key pair TIME/DIV (VAR).

Key sequence:

TIME/DIV

s VAR ns

AUTO

RANGE

Key pair to adjust the MAIN TB time scale for fine or coarse steps

Toggle key to switch the AUTO RANGE function of main timebase.

Page 166
Image 166
Fluke PM3370B user manual Main Timebase Manual + Automatic, 46FUNCTION Reference, Function of key pair TIME/DIV VAR, VAR ns