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Other than the scope module, the A81 Current Board, the A6 Direct Digital Synthesis
Board, and the A3 Mother Board, provide the other functions in the 5820A. Digital
controls are provided by the 5520A-4002 for the front panel display and by 5520A-4009
Out-Guard CPU on the rear panel for all external and internal communication.
The A6 provides low frequency marker frequencies, the wave generator functions and
also contains the acquisition circuitry used in the dc voltage measurement. In addition,
the main voltage reference signals are generated on this board.
TheA3 is used to provide the routing for all control signals from the guard processor and
the signal path for all low frequency signals including the voltage sense signals. An
auxiliary input, Auxin, is a feature that allows a signal to be routed from the front panel
to the output port.
Optional features for the 5820A include 5-channel multiplexing capability and GHz
extended frequency capability. The 5-channel option allows the output signals to be
routed to one of five output ports. The GHz (gigahertz) option provides a 2.1 GHz
leveled sine and 150 ps fast edge. Information about the optional feature can be found in
the "Options" chapter of this manual.
In the following discussion, the circuit boards are generally referenced by
their last two digits. As an example, the 5820A-4055 Main Scope Board is
referred to as the A55.
2-2.
Voltage Mode
All ac and dc voltage function signals are generated from the A51 Voltage/Video Board,
a daughter card to the A55 Main Scope Board. A dc reference voltage is supplied to A51
from the A6 Direct Digital Synthesis Board; this reference is used for all dc and ac
amplitudes. All frequency signals (clock) are generated on the A55. The output of the
A51 is passed to the A55 board, which then passes through the A90 Edge/Attenuator
Board. The signal is then passed to the front panel high frequency switch. The dc
reference signal is used to generate both positive (+) and negative (-) dc and ac signals
that are amplified or attenuated to provide the complete range of output voltage signals.
Output trigger capability is available with the ac voltage signal.
2-3.
Edge Mode
The edge clock originates on A55 and is used on A90 to generate the < 300 ps edge
signal. The edge signal is passed through the attenuator section of A90 and then, like all
of the signals, is passed to the front panel high frequency switch. Output trigger
capability is available with this signal.
2-4.
Leveled Sine Wave Mode
Leveled sine wave signals from 50 kHz to 600 MHz are produced on A55. The leveled
sine wave signal is passed from A55 to the A90. The A90 provides range attenuation and
also contains a power detector that maintains the amplitude flatness across the frequency
range. The signal is then passed to the front panel high frequency switch. Output trigger
capability is not available with this signal.
2-5.
Time Marker Mode
There are 4 primary "ranges" of time marker operation: 5 s to 50 ms, 20 ms to 2 s, 1 s
to 20 ns and 10 ns to 2 ns.
Note
Theory of Operation
Introduction
2
2-7
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