Fluke 5820A, Service Manual

Page: 31 / 158

Theory of Operation
Introduction
2
2-3
2-1. Introduction
The following discussion provides a brief overview of the following 5820A operating
modes:
•
Voltage
•
Edge
•
Leveled sine wave
•
Time marker
•
Wave generator
•
Video
•
Pulse generator
•
Input impedance
•
Overload
•
Current
•
5 Channel Option
•
DC Volts Measure
•
GHz Option (2.1 GHz Leveled Sine and Fast Edge).
This discussion will allow you to identify which of the main plug-in boards of the
Calibrator Mainframe are defective. Figure 2-1 shows a block diagram of the 5820A.
Note that while ac power is filtered on the A3 Mother Board, most supply voltages are
derived on the A80 Voltage Board.
The components in the scope module are shown in Figure 2-2. A signal diagram is
shown in Figure 2-3. The scope module consists of the following:
•
The A55 Main Scope Board, which generates leveled sine, marker, capacitance
measurement, and trigger.
•
The A51 Voltage/Video Board, which generates precision dc and ac low frequency
square wave, video, overload measurement and resistance measurement.
•
The A90 Attenuator/Edge Attenuator, which attenuates the signal by 0 to -48 dB and
generates the < 300 ps edge.
•
The A52 Pulse Board, which generates pulse generator signals.