Theory of Operation
4–14
1735 HD High Definition Waveform Monitor
The front-panel Light-Emitting Diode (LED) matrix is driven by U33 through
U34. Each individual LED’s data is written in when /WR and the data input
(U34, pins 2–9) are low. Data is latched when /WR goes high. LED refresh
occurs continuously.
NOVRAM.
U42 and U35 form the master microprocessor NOVRAM (non-volatile
memory) that retains the current front-panel and auxiliary control status. Data is
written in and read out through pins 3 and 4; the master microprocessor controls
data in and out along with providing the serial clock. Each RAM has its own
enable provided by the master microprocessor. These three lines (Clock,
Read/Write, and Enable) are activated when the power is turned on, when any
front-panel switch is pressed, or when a store/recall is requested.
U38 detects the loss of instrument power in time for the NOVRAM to execute a
save operation. When the +5 V supply drops a few hundred millivolts, pin 7 is
pulled low, causing the NOVRAM to store the current status. The front panel
and auxiliary control data is saved in milliseconds when the power starts to drop
below safe operating levels for the NOVRAM. U41 is a three-terminal regulator
operating from the +13 V supply. As soon as the +13 V raises enough to provide
a +5 V output from U41, the NOVRAM recalls the data saved so that it is
available to the microprocessor when all supplies are up to their operating
tolerances.
Master to Readout Interface.
The CRT readout is drawn with a series of dots. Port
4 of the master microprocessor (U33) defines the horizontal component of the
readout dot, while port 5 defines the vertical component of the dot. U39 and U36
are current output DACs. U43A and B convert the readout DAC output current
to voltage.
R156 and R145 adjust the position of the readout on the CRT. Readout gain
adjustments are in the horizontal and vertical amplifier circuits. The horizontal
and vertical readout is enabled by ROEN from Port 6 of U33.
Summary of Contents for 070-8462-03
Page 5: ......
Page 13: ...Table of Contents viii 1735 HD High Definition Waveform Monitor...
Page 19: ...Preface xiv 1735 HD High Definition Waveform Monitor...
Page 20: ...Getting Started...
Page 21: ......
Page 35: ...Installation 1 14 1735 HD High Definition Waveform Monitor...
Page 36: ...Operating Basics...
Page 37: ......
Page 63: ...Operating Basics 2 26 1735 HD High Definition Waveform Monitor...
Page 64: ...Specifications...
Page 65: ......
Page 75: ...Specifications 3 10 1735 HD High Definition Waveform Monitor...
Page 77: ......
Page 78: ...Theory of Operation...
Page 79: ......
Page 109: ...Theory of Operation 4 30 1735 HD High Definition Waveform Monitor...
Page 110: ...Performance Verification...
Page 111: ......
Page 134: ...Adjustment Procedure...
Page 135: ......
Page 158: ...Maintenance...
Page 159: ......
Page 163: ...Preventive Maintenance 7 4 1735 HD High Definition Waveform Monitor...
Page 179: ...Corrective Maintenance 7 20 1735 HD High Definition Waveform Monitor...
Page 181: ...Repackaging 7 22 1735 HD High Definition Waveform Monitor Figure 7 10 Repackaging...
Page 182: ...Replaceable Electrical Parts...
Page 183: ......
Page 252: ...Diagrams...
Page 253: ......
Page 256: ...Replaceable Mechanical Parts...
Page 257: ......
Page 265: ...Replaceable Mechanical Parts 10 8 1735 HD High Definition Waveform Monitor...
Page 266: ...Appendices...
Page 267: ......
Page 270: ......
Page 271: ......