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M3DVQ wrote:If you only want to use it with crystal controlled sources (e.g. a computer) then you can run the counters from a crystal clock divided down and re-synchronise it to the line pulses to stop it drifting enough to cause a picture tear. This is what I did with my oscilloscope driver circuit and it works very well.
Viewmaster wrote:M3DVQ wrote:At the pixel clock rate of 19.2kHz a suitable crystal would be 1.2288 mHz. Could you tell me where you obtained your crystal ?
Steve Anderson wrote:Viewmaster wrote:M3DVQ wrote:At the pixel clock rate of 19.2kHz a suitable crystal would be 1.2288 mHz. Could you tell me where you obtained your crystal ?
You could use a 12.288MHz Xtal (which is a standard value...and cheap) and divide that by 10, half of a HC390...
Steve A,
Viewmaster wrote:Gee, many thanks for that, Steve. I didn't realise that our NBTV pixel rate could be obtained from a standard xtal.
M3DVQ wrote:For my scope driver I used a 3.2768MHz crystal divided down by 64 to generate a 51.2kHz clock. :
Steve Anderson wrote:I was going to suggest the 4060 but be careful if you're going to use the CD/HEF version at 5V, it's maximum frequency is limited, worst case to 3.5MHz. At 5V use a HC4060, good to 80MHz plus.
Steve A.
Viewmaster wrote:BTW, have just finished 200 soldered joints....only 3,300 more to go to get into the asylum.
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