Anritsu 373XXA - Manual (Page 108)

7-4
DIGITAL SUBSYSTEM
ASSEMBLIES The following paragraphs briefly describe the major assemblies that com-
prise the 373XXA Digital Subsystem. The digital subsystem provides all
system control, I/O interface, digital signal processing, and data pre-
sentation functions.
The major assemblies that comprise the 373XXA digital PCB subsys-
tem are listed below. Refer to Figure 7-3, at left.
q A9, Main Processor PCB
q A13, I/O Interface #1 PCB
q A14, I/O Interface #2 PCB
q A15, Graphics Processor PCB
q A16, Hard Disk PCB
q A18, Rear Panel Interface
q Rear Panel Assembly
q Front Panel Assembly
q Floppy Disk Assembly
q A24, VME Bus Terminator PCB
A9 Main Processor
PCB Assembly
The major components that comprise the A9 Main Processor PCB are:
q 68040 Microprocessor (w/ integrated co-processor) – This is the
CPU for the 372XXB system.
q 4 MB DRAM – This is the main system memory. This memory is
volatile (non-battery backed). During normal operation, it stores
the 372XXB software that is loaded from disk at power-up.
q 8 KB BBRAM – This auxiliary memory chip contains a back-up
battery that is continuously recharged whenever power is ap-
plied. (The back-up battery has a four year minimum life span.)
This chip also contains real time and date clock functions. It is
used to store low level boot-up parameters, ALC calibration data,
source frequency calibration data, and service log header data.
q 512 KB SRAM – This auxiliary memory is backed-up by a
non-rechargeable Lithium battery that provides 200 days (maxi-
mum) of power-off protection. It is used to store current and
saved front panel setups, trace/normalization data, current RF
calibration data, current sweep frequency data, flat power cali-
bration data, and the service log error list.
q VME Bus interface chip – This chip is used to interface the Main
Processor PCB to the A13, A14, and A15 digital PCBs (via the
VME bus interface).
q SCSI Bus interface – This chip is used to interface the Main Pro-
cessor PCB to the A16 Hard Disk PCB.
SYSTEM DESCRIPTION DIGITAL SUBSYSTEM ASSEMBLIES
373XXA MM 7-13