# what is the conversion time of an adc to monochrome sd?

I'm trying to figure out is how fast would an ADC need to be (The conversion time) in order to decode and analog TV signal to a monochrome SD (720x480) movie at 24 frames per second? This is assuming it is converting at at a one conversion per pixel rate?

Any idea how I could figure this out?

Thanks to all who responded, I got it.

conversion time = 1/(total number of pixels converted in one second)

Well for PAL its 625 lines at 25Hz and estimated horizontal 1000 pixels per line, allow 10% for blanking time,
15 to 20MSPS or so?

To write to an SDcard at that speed requires video compression hardware and native mode interface.

Is 1 / (720 x 480 x 24) really too hard a sum to do?

MarkT:
Well for PAL its 625 lines at 25Hz and estimated horizontal 1000 pixels per line, allow 10% for blanking time,
15 to 20MSPS or so?

To write to an SDcard at that speed requires video compression hardware and native mode interface.

Active line length is only 52 us, and there are only 576 active lines.

I can't see where the SD card requirement has crept in.

Is 1 / (720 x 480 x 24) really too hard a sum to do?

The division is a tough one.

rcAven:
I'm trying to figure out is how fast would an ADC need to be (The conversion time) in order to decode and analog TV signal to a monochrome SD (720x480) movie at 24 frames per second? This is assuming it is converting at at a one conversion per pixel rate?

Any idea how I could figure this out?

Thanks to everyone who responded I got it.