Agilent Technologies 8753ES Option 011 Service Manual page 366

Theory of Operation
Digital Control Theory
EEPROM
EEPROM (electrically-erasable programmable read only memory) contains factory set
correction constants unique to each instrument. These constants correct for hardware
variations to maintain the highest measurement accuracy. The correction constants can be
updated by executing the routines in
Digital Signal Processor
The digital signal processor receives the digitized data from the A10 digital IF. It computes
discrete Fourier transforms to extract the complex phase and magnitude data from the
4 kHz IF signal. The resulting raw data is written into the main RAM.
A18 Display
The A18 display is an 8.4 inch LCD with associated drive circuitry. It receives a +3.3 V
power supply from the A19 GSP, along with the voltage generated from the A27 backlight
inverter. It receives the following signals from the A19 GSP:
• digital TTL horizontal sync
• digital TTL vertical sync
• blanking
• data clock
• digital TTL red video
• digital TTL green video
• digital TTL blue video
A19 GSP
The A19 graphics system processor is the main interface between the A9 CPU and the A18
display. The CPU (A9) converts the formatted data to GSP commands and writes it to the
GSP. The GSP processes the data to obtain the necessary video signals, which are then
used for the following purposes:
• The video signals are used to produce VGA compatible RGB output signals, which are
routed to the A16 rear panel.
• The video signals are converted by an LVDS (low voltage differential signaling) driver
which translates the signals to low level differential signals to help eliminate radiated
emissions. The converted video signals are then routed to the A2 assembly, where they
are received and sent to the A18 display.
The A19 assembly receives the +5 VCPU which is used for processing and supplying power
to the A27 backlight inverter (+5 VCPU) and the A18 display (3.3 V).
12-12
Chapter 3 , "Adjustments and Correction Constants."
Chapter 12