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Synchronous Digitalization Of TV Images

IP.com Disclosure Number: IPCOM000049728D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Baier, H: AUTHOR [+4]

Abstract

For digitalizing TV images it is essential that the individual picture elements (pels) are always derived from a predetermined position. Only in such cases is it advisable, for example, to add or subtract images.

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Synchronous Digitalization Of TV Images

For digitalizing TV images it is essential that the individual picture elements (pels) are always derived from a predetermined position. Only in such cases is it advisable, for example, to add or subtract images.

More conventional methods use the synchronizing signals of the TV camera (horizontal and vertical synchronizing signals) to start external timing means, whose count pulses serve as control signals for the video analog to digital (A/D) converter. External timing means must be quartz-controlled to ensure a high sampling accuracy. Synchronizing the camera oscillator with the oscillator of the timing means is technically elaborate because of the analog regulating systems required.

The method shown in the block diagram uses a TV camera which is externally synchronized by an external frequency generator. From this generator (30 MHz), a 1 MHz signal, controlling a TV synchronizing signal generator, is derived by a frequency divider (1:30). The signal generator supplies the synchronizing signal for the TV camere.

By means of a frequency divider (1:2) and a control logic, to which also the vertical and horizontal synchronizing signals are applied, the external frequency generator (30 MHz) supplies the 15 MHz control signal for the analog to digital converter. This leads to a rigid phase relationship between the TV camera syncronizing signal and the control signal of the analog to digital converter.

In addition, the TV synch...