Keysight Infiniium 8000 Series, Руководство по обслуживанию

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Chapter 8: Theory of Operation
Block-Level Theory
152
Power Supply Assembly
The AC input to the power supply is 100–240 VAC, +/- 10%. Maximum input power is
440W. The AC input frequency is 47 to 63 Hz.
Filtered voltages of +5.1 V, –5.2 V, +12.2 V, 3.3 V, and –12.2 V are supplied and
distributed throughout the oscilloscope.
FPD Monitor Assembly
The Flat Panel Display (FPD) monitor is a thin film liquid- crystal display (TFT- LCD).
This FPD is an 8.4- inch diagonal, 1024 by 768 pixel XGA color monitor. The assembly
re3.3 V and +12 V from the power supply.
A twin fluorescent back light provides illumination for the LCD. The Backlight Inverter
assembly converts the +12 V to +300- 1000 volts (acrms) and drives the back light.
Acquisition System
The acquisition system includes four attenuator assemblies on the acquisition board.
The attenuators condition the signal, which is then digitized and stored by the acquisition
board. The graphics board provides the system control interface from the motherboard,
and also interfaces the acquisition board to the display board for display of the acquired
data. More detailed theory on the acquisition system follows this top- level block theory.
Attenuators
The attenuators provide the appropriate impedance matching and all the attenuation
and gain selection for each input channel. The attenuators are part of the acquisition
board.
Front Panel
The front panel is read and controlled by a micro controller IC. This device contains
a microprocessor, RAM, ROM, and a DUART for communication with the microprocessor
on the main assembly. The micro controller is located on the keyboard and communicates
with the system control circuitry through an RS- 232 cable. It reads the keys and knobs
and controls the LED indicators.
The elastomeric keypad has 30 keys, all dedicated to a single function to improve ease
of use. A conductive element on the inside of each key shorts a gap on the underlying
keyboard circuit. The keyboard controller detects this short and sends the proper
keypress information to the system controller on the motherboard.
There are eleven dedicated knobs. Each knob controls a mechanical encoder. The output
of the encoder is a 2- bit gray code that is read by the micro controller for direction
and distance turned.
A push button controls the power through a Remote Inhibit sense line that is routed
to the power supply.
Disk Drives
The hard disk drive is a high- capacity, shock- resistant unit. It is used to store the
oscilloscope operating system and certain system configuration data.
The drive can also be used to store and recall oscilloscope setups and waveforms.