Theory of Operation
WVR610A & WVR611A Waveform Rasterizers Service Manual
3- 5
The embedded audio path starts at the waveform processing engine. First the
audio samples are extracted from the serial digital video data using a
12.288 MHz oscillator and sent to the audio board. At the audio board, the
streams are multiplexed into the AES decoders and then follow the same path as
the AES data. The user can choose to have the de-embedded audio output on the
AES B port.
Audio Outputs
There are two audio outputs, analog and AES. Both outputs always follow the
source that is currently selected for the audio bar display. The analog outputs can
come from any input. The selected signal output from the FPGA, is converted
from digital to analog and then sent as a balanced output to the 37-pin rear panel
connector.
The AES outputs are only available when the input is embedded. In this case, the
AES B connectors can be configured as outputs, and the embedded is sent out on
the AES B connectors.
Fault and Fan Block Diagram
There are two circuits not shown on the signal flow block diagram, the Fan
control and the bus that drives the front-panel “Fault” LED. Refer to the
High-level fault and fan block diagram
(on the foldout page in Section 8) while
reading the associated paragraphs below.
The fan circuit senses the temperature to set the fan speed. Each fan has a
tachometer output to indicate fan speed so the circuit can run the fans at low
speed without stalling. The slower of the two fans controls a power supply that
provides the voltage for both fans. If a fan is not turning, the circuit senses the
stall and asserts the fault line and a line to the control processor so the event can
be entered in the diagnostic log.
The front panel “Fault” LED is driven by a line accessible by most of the
instrument. The concept is to provide fault information independent of the
control processor, since it may not always be working. If any circuit detects a
fault, it pulls the fault line low. This line is what is called a “wire--or” because
any circuit can assert it by pulling it low. Circuits are also expected to assert a
local LED when asserting the fault line. Because of this local LED, a technician
should be able to look inside the box and see a red LED near the site of the fault.
Faults are usually also sent independently to the control processor.
For details about the circuits that can assert the fault light and their associated
local LEDs, refer to the
Troubleshooting
on page 6--5.
Summary of Contents for WVR610A
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Page 14: ...Table of Contents x WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 18: ...Service Safety Summary xiv WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 22: ...Preface xviii WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 23: ...Specifications...
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Page 53: ...Operating Information...
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Page 90: ...Operating Basics 2 36 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 132: ...Changing Instrument Settings 2 78 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 139: ...Theory of Operation...
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Page 147: ...Performance Verification...
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Page 201: ...Adjustment Procedures...
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Page 204: ...Adjustments 5 2 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 205: ...Maintenance...
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Page 228: ...Repackaging Instructions 6 22 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 229: ...Options...
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Page 234: ...Options and Accessories 7 4 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 235: ...Diagrams...
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Page 243: ...Replaceable Electrical Parts...
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Page 246: ...Electrical Parts List 9 2 WVR610A WVR611A Waveform Rasterizers Service Manual...
Page 247: ...Replaceable Mechanical Parts...
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