| 1_ |
NTSC:
Introduction |
| 2_ |
Scanning,
Timing/Sync, Sync Recovery, Numbers |
| 3_ |
Gain
& Offset, D.C. Restoration, Gamma Correction |
| 4_ |
Resolution,
Bandwidth, Spectrum |
| 5_ |
Color
Physics: Eye, CIE |
| 6_ |
Color
Encoding: Color Bars, Camera,
RGB,
YIQ, Color Subcarrier |
| 7_ |
Color
Decoding: |
| 8_ |
Digital
TV/Graphics: ADC-DAC, Frame Buffers, Timebase Correction, VGA |
| 9_ |
VCR:
Spectrum, Circuits |
| 10_ |
Circuits & Practices:
D.C. Restore, Proc Amps, DAs |
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Loop Thru
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| Loop Thru is a method of
driving several monitors from a single Video Source. All but the last monitor
are said to be "Bridging" the Video. |
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Video Amplifier
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| Note it is a Non-inverting
emitter coupled arrangement, with high frequency peaking.
Video Amplifiers NEVER invert
the Video signal. |
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Low Noise Video Interconnection
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| Noise immunity is enhanced
by preserving the electrical isolation of the coaxial cable's shield; as
well as proper terminations of each end.
Note that input & output
"ground returns" are connected; Isolation from chassis, bulkheads, and
shields are preserved. |
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Genlock
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| Genlock is where several
video sources are synchronized with each other, e.g., either a master sync
generator or a camera or a VTR/VCR.
However it cannot be used
synchronize a VTR/VCR to an external source; a TimeBase Corrector (TBC)
is used for that purpose. |
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Auto Blacklevel
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| As scenes change, i.e.,
background lighting, etc., some image detail can be lost if the maximum
white & black peaks are allowed to exceed certain limits (White: 100
ire; Black: 10 ire). The Auto Black Level System is designed to prevent
this loss. |
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TimeBase Corrector (TBC)
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| The TimeBase Corrector is
similar to Genlock, but able to "genlock" an unsynchronizable source like
a Video Tape Recorder (VTR) by the use of a Frame Store (frame buffer). |
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Barstow-Christopher Function
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| Effect of Noise at various
frequencies verses perceived picture disturbance.
Low frequency noise cause
the greatest Disturbance; some high frequency noise can actually enhance
image edge resolution. |
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Gamma Correction
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| Gamma correction is made
necessary due to the Exponential Voltage- to -Light transfer function of
the Display CRT. |
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Sequential Scan Color Camera
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| Sequential Color Cameras
have the Advantages of needing only one BW sensor; inexpensive optics;
high resolution; no registration errors (as with 3 sensor cameras).
Disadvantage: motion aliasing.
The "Apollo" and "Space
Shuttle" used this type of technology. |
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Television-For-EEs
Television
Technology for Engineers, Technicians & Hobbyists
| Television
encompasses more subject areas than any other single technology. You learn
switching power supplies, perception, wireless communications, ergonomics,
physics: --the list is endless... |
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Implementation
(Overview)
| One could use a small brushless
DC motor (e.g., floppy/HD spindle motor).
The color wheel uses three
RGB filters; there is a single notch (index) cut in the edge of the wheel
where a photo interrupter is used to sync the Phase Locked Loop (PLL) to
the Vert Sync/3.
For control of frame alignment,
you can insert a oneshot between the photo interrupter (or the sync pulse)
and the phase detector (MC 4044) to give you control over when the CCD
exposes for a particular field.
Remember after vertical sync,
CCDs allow exposure time, and then dump the image for readout; this can
happen in 1/50,000 of a second to ~15 msec, depending on the brightness
of the scene. Just when this process begins isn't clear; but, after the
"dump" the CCD throws away any successive exposure until the next frame.
So when adjusting the delay--from the oneshot--do it in low light --longest
exposure. |
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