Theory of Operation
3--4
TPS2000 Series Digital Storage Oscilloscopes Service Manual
Power Supply and Battery System
The IO board accepts the power input for the oscilloscope from either a 15 VDC
external supply or from one of two internal Lithium-Ion battery packs. The
battery packs are SMBus compliant and user replaceable.
A microcontroller manages the routing of power from the DC input and the 2
battery packs. It also manages the charging of batteries and communication to the
Acquisition board.
The instrument cooling fan is powered by the IO board. The fan can be switched
on and off, having its voltage varied by signals from the Acquisition board.
Power for the LCD backlight inverter board is supplied by the IO board. A
dimming voltage, derived from a PWM pulse train and RC low-pass filter,
controls the brightness of the backlight.
RS-232 and Parallel port signals are passed from the Acquisition board through
the IO board to their rear-mounted connectors.
Display Module
The Liquid Crystal Display pattern consists of 320 columns with 3 subcolumns
and 240 rows, and has associated drivers and a backlight. The backlight is based
upon a 5 mA top-light fluorescent tube.
Front Panel
All switches, position encoders, and LEDs are mounted on the Front Panel board
of the two-channel oscilloscope. Additionally, an IC on this board provides
buffering and multiplexing of switch signals for the Acquisition board. (Two
signals and a sense line are provided by the Acquisition board to support the
front panel.) One of these lines resets the scan; a second clocks the scan to the
next position; and the sense line receives the current state of the selected switch
or encoder position.
For the encoders, some amount of debouncing occurs inside the front-panel IC.
All key debouncing is handled in the display ASIC on the Acquisition board.
Two-Channel
Oscilloscopes
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Страница 12: ...Table of Contents vi TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 16: ...Service Safety Summary x TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 20: ...Preface xiv TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 42: ...Theory of Operation 3 6 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 62: ...Adjustment Procedures 5 10 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 90: ...Maintenance 6 28 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 92: ...Options 7 2 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 94: ...Electrical Parts List 8 2 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 96: ...Diagrams 9 2 TPS2000 Series Digital Storage Oscilloscopes Service Manual...
Страница 106: ...Replaceable Parts 10 10 TPS2000 Series Digital Storage Oscilloscopes Service Manual...