Section 4
4-24
4.3.2. Nanovolt Detector Principles of Operation.
4.3.2.1. Introduction.
The nanovolt detector consists of the following functional blocks:
a) Power Supply (Guildline drawing number 19103.01.02) - generates +5
volts, ±15 volts, and ±30 volts.
b) Nanovolt Detector CPU PCB (Guildline drawing number 19855.01.02) -
consisting of a microprocessor with its input/output latches, random access
memory, read only memory, GPIB interface, serial communication interface
(fiber-optic).
c) Analog to Digital (A/D) Converter PCB (Guildline drawing number
19502.01.02) - with high speed integrator.
d) Amplifier/Attenuator PCB (Guildline drawing number 19503.01.02) - with
high gain.
e) Software - the nanovolt detector operating software in read only memory.
The functional blocks are described below.
4.3.2.2. Nanovolt Detector Power Supply (19103.01.02)
A single transformer with two secondary windings drives three standard series-pass
regulated supplies. The supplies have a rectifier, filter, three terminal monolithic
regulator and output filter.
The ±15 V is used to power the A/D Converter PCB and the Amplifier/Attenuator
PCB. The ±30 V supply is used to power the attenuator circuitry on the
Amplifier/Attenuator PCB. The +5 V is used to power the nanovolt CPU PCB.
4.3.2.3. Nanovolt Detector CPU PCB (19855.01.02)
The nanovolt detector CPU PCB contains a microprocessor, memory and
input/output devices. The input/output devices interface to the
Amplifier/Attenuator PCB and to the A/D Converter PCB. The I/O devices also
interface to the GPIB (IEEE-488). These sections of the CPU PCB are represented
on schematic 19855.01.04.
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