Crt Display Section; Power Supply; Digitizer Section - Fluke Autoranging CombiScope PM3370B Reference Manual

PRINCIPLE OF OPERATION 2 - 3

2.5 CRT DISPLAY SECTION

This section determines the intensity and focusing of the signal on the screen.
The intensity of trace and text/cursors can be adjusted separately with the
controls TRACE INTENSITY and TEXT INTENSITY. The FOCUS control
determines the sharpness of text and traces. Moreover focusing is controlled such
that changes in intensity do not affect display sharpness.

2.6 POWER SUPPLY

This POWER SUPPLY converts a wide range of line input voltages into stable
supply voltages that feed the circuits in the oscilloscope. Also the very high
voltages for the CRT are made by the power supply. Another output signal is used
to trigger the MTB if 'line' is selected as trigger source. Memories in the
oscilloscope are supplied by a MEMORY BACKUP battery if line voltage is
switched off.

2.7 DIGITIZER SECTION

In DIGITAL MODE the CH1 ... CH4 (PM3370B/80B/90B; CH1, CH2 and TRIG
VIEW) input signals are applied to the DIGITIZER AND TEXT GENERATOR
where they are digitized and stored in a memory. The signal storage is initiated by
pulses from the TRIGGERING.
Also the generation of text/cursors is done in the block DIGITIZER AND TEXT
GENERATOR.
For display on the CRT, the digital information is converted into analog and
applied to the final amplifiers for VERTICAL and HORIZONTAL deflection. The
FOCUS and INTENSITY parts are controlled in a similar way. Switching between
ANALOG MODE and DIGITAL MODE is done via the ANA/DIGI switches that are
operated by the DIGITIZER AND TEXT GENERATOR. The switches are
incorporated in the inputs of the output stages of Final Y, Final X, Intensity and
Focusing.