Philips TVette showing Test Card F [11K]

A 405 LINE TEST CARD SIGNAL GENERATOR

Designed by myself and I only wish 405-Alive magazine
were around long enough to publish it, which they wern't.

Perdio Portorama showing test card C [7K]

Block Diagram [4K]

The basic idea behind this design is to store one complete image (i.e. two interlaced scans) in an EPROM in a linear fashion, complete with all the sync pulses and front/back porches. The output of the EPROM can then be fed to a suitable D.A.C. so as to produce the required video signal. Of course, this method could be applied to the generation of any video signal format.

A PC based package software package allows any image (in .BMP format) to be converted to an appropriate EPROM image.

The project is broken down into the following sections :-

The 405-line TV Waveform An overview of the signal we are trying to generate
EPROM Encoding How the data is encoded in the EPROM.
EPROM Design The EPROM size, timing and output logic
The Counter The EPROM address counter
The Master Clock The master clock that drives the circuit
D/A Conversion Converting the EPROM data to an analogue signal.
 
Skip the waffle, just download it

Thanks go to Peter Brown who had a working EPROM blower, working 405-line set and the necessary debugging skills.

Old end-of-transmission screenshot [4K]


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J.Evans 2002
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Last updated
1st August 2002