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Time Base Correction: ES 2204-T Time Base Correction
(TBC)
Unit
Synchronization:
The ES 2204-T Time Base Correction (TBC) Unit (http://www.dps.com) is a full
frame 512 line TBC unit. The S-VHS
pathway through the TBC unit insures correction of any synchronization problems
with the input video without loss of VHS information content.
Brightness - Contrast:
The digital rotary dial on the ES 2204-T adjusts brightness and contrast when
black or video switches are pressed. The
digital rotary dial sets the processing amplifiers to unity gain (output signal
has the same voltage values as the input signal), SETTING 3, green light on
brightness, contrast. The range of the digital dial is from -127 to +127 for
brightness and contrast. Pressing
and holding the Unity switch (far right most key) for a few seconds resets all
the processing amplifiers to unity gain. The
unity setting is signified by a series of flashing red lights.
In the VCR still mode, or slow advance, the output signal is monitored on the
image display monitor. Dark, low
light level video now becomes bright as daylight for enhanced viewing.
The brightness and/or contrast can be adjusted by selecting the video or
black switch and rotating the digital dial.
Motion Blur:
While the VCR is advancing through the images, set the “Freeze Frame/Field”
switch to “FIELD”. Press
“TAKE”. Three fields are frozen
and loaded into digital memory in the TBC.
Rotating the digital dial advances the captured video through three
fields. The effect is to lessen,
reduce or even eliminate motion blur.
Time Lapse to Real Time
- Quasi Real Time for slow
play time lapse VCR tapes:
Slow play or long play time lapse video tapes can be made to appear as Quasi
real-time for display on regular VCR's played in their normal two (2) hour mode.
This feature is a great aid to the investigator(s), the witness(es) and juries.
The slow play or long play time lapse video is played back on the
continuous mode VCR unit. The video signal is routed via the SVHS pathway
through a full frame time base correction unit with intensity adjustment.
The speed of the playback unit is adjusted manually for Quasi real-time motion.
The video signal is recorded on the time lapse VCR in normal two (2) hour mode.
Though the SVHS pathway is used throughout the entire signal route, only
the VHS signal is actually played back and recorded. The wider SVHS
pathway allows for minimal signal loss due to its wider bandwidth.
The resulting VHS recorded tape can now be played in any regular VCR unit
with less or more delay between images providing Quasi real-time motion.
Place the original VCR tape in the Panasonic AG 7350
(jog/shuttle and continuous play) VCR.
Press “Play” and rotate the outer dial of the jog/shuttle control on
the Panasonic AG 7350. The outer
dial, shuttle control, moves the tape forward or backwards, across the helical
scan rotating read-write heads from one to eleven times real time, (1X to 11X).
Find the region of interest to record.
Find the starting position, advance the shuttle dial until real time or
quasi real time motion appears on the monitor.
Most situations require a slightly slower than real time two (2) hour
mode setting. This slightly slower
than real time speed gives the eye more opportunity to comprehend the images
without distorting the real time effect. Find
the optimal real time setting, often just a few degrees, ˜5°
clockwise from the shuttle control still position, then press “STOP”.
Without changing the shuttle dial setting, rewind the tape on the AG 7350
to the beginning, or just behind the starting point of the region of interest.
Insert a VHS tape into the NAVCO 2700 (the copy tape) and set the NAVCO
2700 to two (2) hour mode (front panel time mode switch - up, down arrow
buttons). Press “Play” on the
Panasonic AG 7350. Just a few
seconds before the start of the scene of interest appears on the monitor, press
“Record” (red button) on the NAVCO 2670.
The Panasonic AG 7350 will now transfer the time base corrected images in
real time or quasi real time to the NAVCO 2700.
The NAVCO 2700 records in real time standard play SP two (2) hour mode.
The VHS copy tape receives the VHS signal using the SVHS pathway through
all of the VCR’s, TBC’s and Multiplexer’s.
Minimal information will be lost to the copy tape.
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