693 Melrose Road
Lottsburg, VA 2251
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Video Encoder/Decoder Model VED-M
Operation Manual
Description
The Video Encoder/Decoder (VED) Model VED-M has two modes of operation, encode
and decode. When GPS data from an external GPS receiver is available, the VED automatically
enters the encode mode. In encode mode GPS data is inserted into camera video in both alpha-
numeric and edge-code format. The edge-code data consists of one bit per video line placed
immediately after horizontal sync. Edge-code data appears at the far left of the screen in a video
monitor capable of underscan. The edge-code is not visible in normal scan. When video
containing edge-code is input, the VED automatically enters the decode mode. In decode mode
the edge-code is read and GPS data is output in simulation of a GPS receiver.
Applications
The VED with video camera and video cassette recorder (VCR) comprise a complete
GPS data acquisition and retrieval system. In the encode mode imagery and GPS data are stored
together on convenient video tape. In the decode mode GPS data is recovered from the playback
video and output in a form compatible with popular moving map programs, thereby allowing
simultaneous viewing of camera picture and map location. Since complete GPS data is stored on
each video field, the VED will output GPS data even when the VCR is paused, or when the input
is a captured video image. For fleet vehicle identification, the VED serial number is included in
the on-screen display. A rotary switch allows GMT or UTC time to be offset to local time. The
hour offset is also displayed to maintain a link to UTC time. Internal switches allow for top or
bottom screen display, and selection of English or metric units.
Power
The VED operates at 100 milliamps with nominal 12 VDC (9-16 VDC) input power.
Input power up to 30 VDC can be used provided that the installation allows for dissipation of 3
watts of heat from the VED enclosure. The power input connector is a 2.1 mm jack with long
barrel to allow use of locking plugs. The center pin is positive and reverse polarity protection is
built-in. Input power is routed through a polycrystalline self-resetting fuse inside the VED to
several pins on the COM connector to provide power to the GPS receiver and other sensors. It is
recommended that the power source be fused at 1 amp for additional protection.
Note:
Some 2.1
mm plugs do not have recessed center pins. Avoid use of these plugs. If the center pin contacts
the barrel of the jack during insertion, a short circuit will occur.
