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I've just posted a Youtube video of the color decoder. The source code for the project is also published under GPL. Both available here:
https://codeandlife.com/2012/09/12/color-composite-video-decoding-with-picoscope-3206b/
Technical details to be added as soon as I get nice illustrations...
Thank you. This gave me the confidence to continue along my original "simple" path. The crucial bit of information was this:
https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation#Analog_QAM
Basically the above section just tells why the multiplication with carrier works as you said it...
Ooh, I think I found something interesting along these topics from Wikipedia, namely the digital filter article:
https://en.wikipedia.org/wiki/Digital_filter
Especially useful seem to be pseudo code implementations for low-pass and high-pass filters that work with discrete digitization...
Yes, the information you linked is about where I am now. NTSC that I'm decoding consists of 525 scanlines, which form two fields of about ~242 horizontal lines each, interlaced to form a single image. The component video signal does not have a horizontal resolution, instead one can think of it...
Yes, I'm digitizing it with a Picoscope 3206B which basically gives me the signal as C array of short values, over 1 million samples taken every 2ms (or 4, 8, 16...). I am already recognizing sync pulses and drawing scanlines using luminousity information, but would also like to add rough color...
Thanks for the link, it was quite informative! Maybe implementing a high pass filter would be one option to get rudimentary color signal out, or even a trap filter, using fourier transformations.
I'm going for a full SW based approach if at all possible, without any external components - just...
Help from experienced digital signal processing specialists is needed! I recently did a nice hack where I digitized a composite video signal from Raspberry Pi using a USB oscilloscope, and decoded it to a B/W video in computer...
I've been using the GNU toolchain for AVR programming, including the avrdude utility to flash the MCUs and set the fuses. A few months ago I started thinking if I could eliminate the command prompt from my workflow entirely, because I was mainly just running the same few commands again and again...
Yes, it was a complete surprise to me, too. I had thought the yellow RCA connector was for S/PDIF audio. Also, the Pi can output both NTSC and PAL signal in multiple aspect ratios. Haven't tried that or different resolutions yet, though.
Hi!
Here's a cool hack I came up with during the weekend, and surprisingly enough, proved to feasible: Capturing composite video NTSC signal with a USB oscilloscope (Picoscope 2204 to be exact, they have a nice C API), and decoding it realtime to emulate a composite display in software...
I do like DipTrace a lot better, mainly because it has a nice, intuitive user interface, unlike Eagle, which causes me constant revulsion and makes me think that the developers have not cared a bit for improving the user experience for the last ten years. Other plusses on DipTrace side is how...
For those of you interested in the DipTrace schematic / PCB modeling suite (or anyone looking for something else than Eagle), I recently recorded a few instructional videos to YouTube showing the different parts of the software, hopefully useful to anyone who'd like a quick peek on the...
When you have a pointer to a struct, you use the arrow operator. When the variable is a struct (in stack), you use the dot:
struct SomeStruct * ss = ...;
struct SomeStruct ss2;
ss->someField = ...;
ss2.someField = ...;
It also seems your "theDataStruct" is either a struct or union, and not a...
Don't know about the specifics of PIC23F configuration, but usual sampling rates for voice are 22 kHz or sometimes even just 11 kHz (saves a bit space but I guess high frequency components do get cut off).
I would also consider the possibility that for some reason the microphone is not...
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