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X and Y oscilloscope signals to composite video converter

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neazoi

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Hello I consider this bare bones spectrum analyzer spectrum_an
I like to display the signal not on an oscilloscope but on a small portable TV having video and RF inputs

So I need a XY to video converter schematic.
Is there any one outthere, I cannot find any.
 

FvM

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So I need a XY to video converter schematic.
Instead of asking for a general XY to video converter, you can simplify the problem considerably by assuming a digital system, that generates the scan signal and receives the Y signal in return. The converter has to provide an image memory and generate the video framing. An older days home computer with TV video display would be a solution. But I guess, that the hardware solution discussed in a recent thread could also provide the conversion, after a respective redesign.
https://www.edaboard.com/threads/197526/
 
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    neazoi

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neazoi

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This is a vga to video adapter for the TV. I have found simple video-to-oscilloscope and VGA-to-oscilloscope adapters on the net that use 555 chips and perform quite satisfactorily. But what I need is the opposite, an XY-signal to video simple circuit.
The analyzer outputs an XY signal so this needs to be converted to video before sending to the TV, as I do not like to mess up with the TV electron gun coils.
Is there any such project out there?
 

betwixt

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It isn't easy on a TV. The trouble is your horizontal scan rate is fixed at 15,625KHz which is far too fast for scanning across the frequency spectrum and you do not have a way to displace the trace vertically to show amplitude. The only way you can do it is to build a conventional spectrum analyzer and a video digitizer to allow slow frequency sweeping to be captured and then displayed at fast scan speed. It is a difficult task!
The advantage of the oscilloscope method is you can control the sweep speed, with a TV it is fixed.

Brian.
 

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This is a vga to video adapter for the TV.
No it isn't.

It's a software video frame generator, that displays a text pattern to video and VGA. My suggestion was to make the µP perform the frequency scan, digitize the amplitude information and generate the video signal sequentially, without involving a video memory.

The classical approach would use a dual port video memory and standard video display hardware.
 

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