Rohde & Schwarz NGMO1 - Function Description; Prozessor Board

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4.2 Function Description
The schedule at the service design concept is to replace the following
modules when a fault occurs.
• Processor board
• Keyboard / Display
• Analog board ”A“ (NGMO1)
• Analog boards ”A“ and ”B“ (NGMO2)
4.2.1 Prozessor Board
Apart from the control processor, its periphery and all data interfaces
the processor board also contains the rectification and filtering for the
electric power supply of the overall unit.
For this purpose the unit is equipped with two separate power supplies
with a transformer each. The mains supply voltage is channel separat-
ed and fed to the transformers via two fusible cut-outs on the processor
board. Separate fuses for 115VAC and 230 VAC are present.
The secondary voltages supplied by the transformers are rectified and
filtered on the processor board. Each of the two power supplies delivers
three non-stabilized direct voltages (approx. 8 VAC, 16 VAC, 21 VAC)
via the lateral connectors to the analog boards. A separate winding of
one of the two transformers generates the processor supply voltage
(+5 VDC) and stabilizes it on the board. On the processor board all di-
rect voltages are indicated by LEDs.
The alternating voltages arriving from the transformers are protected by
SMD-fuses directly after the connectors.
The processor establishes the data exchange between the remote con-
trol interfaces (RS232 and IEEE) and the signal processors on both
analog boards, interprets and saves measuring data as well as control
commands from the interfaces and from the keyboard. It additionally
presents data and modes on the display.
The periphery of the control processor consists of a main memory, an
EEPROM for storage of calibration data and adjustments as well as a
Flash-ROM to store the Firmware.
4-2 3.00 / 05-2014