Nope. I don't really have an overview of which one to get for a 60-pin system.Do you have a flashcart?
Since I bothered to play around with the Pac-Land image and write down some numbers:NewRisingSun wrote:color $31 at 319.9 degrees (nominal: 330)
color $36 at 113.1 degrees (nominal: 120)
Blue $31 at 316-323° (nom: 330)
Blue $11 at 323-335° (nom: 330)
Magenta $15 at 84-90° (nom: 90)
Peach $36 at 109-117° (nom: 120)
Brown $07 at 150-158° (nom: 150)
Orange $27 at 140-146° (nom: 150)
Green $1B at 268-274° (nom: 270)
I clearly need to put more effort into filter design to reduce those ranges.
The Everdrive N8 has a Famicom 60-pin option, though I can also confirm that the PowerPak and Everdrive N8 72-pin both work on a Famicom using simple 72-60 pin converters.NewRisingSun wrote:Nope. I don't really have an overview of which one to get for a 60-pin system.Do you have a flashcart?
Eh, the matlab/octave fragment was more for proving to myself that your methodology is correct. It clearly is, and now I think the only remaining parameter to be explored is just how much variation we should anticipate across all the hardware variants.NewRisingSun wrote:I don't use Matlab, but I can post the C source to my NTSC decoder that takes the .raw captured file and outputs a .rawraw RGB file, if that helps you.
Is there an easy way to calculate how "non-ideal" either not a square wave or not a sine wave this is? Is the "skewness" test the right one?
Skewness of 10000 points of a sampled ideal sine wave appears to be approximately 0, but skewness of the huge patch of color $31 is 0.126 and the mean is very slightly higher than the median (Δ=0.336).
For the record, I have used the same setup to measure the composite video output of a Tandy 1000 computer. It can output six hues at two luminance levels. The two levels are different for each of the hues. I measure no level-specific phase shift beyond the noise level between the two luminance levels of each hue:
Code: Select all
Color 1: 0.008638 (blue, nominal: 0) Color 2: 223.742996 (green, nominal: 225) Color 3: 269.025116 (cyan, nominal: 270) Color 4: 92.503235 (red, nominal: 90) Color 5: 46.509937 (magenta, nominal: 45) Color 6: 180.940750 (yellow, nominal: 180) Color 9: 359.858380 (blue, nominal: 0) Color A: 223.127350 (green, nominal: 225) Color B: 268.470940 (cyan, nominal: 270) Color C: 91.619957 (red, nominal: 90) Color D: 46.090595 (magenta, nominal: 45) Color E: 179.678253 (yellow, nominal: 180)
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- Palette-RP2C02E-RCA.raw: Signal from the yellow RCA socket at the back of the Sharp Twin Famicom AN-500B (PPU: RP2C02E-0)
- Palette-RP2C02G-PPU.raw: Signal from the PPU's output pin of the Sharp Twin Famicom AN-505BK (PPU: RP2C02G-0)
- Palette-RP2C02G-RCA.raw: Signal from the yellow RCA socket at the back of the Sharp Twin Famicom AN-505BK (PPU: RP2C02G-0)
I am posting these files without comment for now, because I am curious about what conclusions other people draw from them, before I share mine.
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At this point, I have no idea what to think any more. Colors $12, $16, and $1A are a different phase offset than the other ones, not restricted to just even or odd phases.
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The first picture shows the result I get when I use my "Simple PAL" decoder --- properly accounting for the phase shift in the V channel from scanline to scanline, but not averaging each scanline's demodulated chroma signal with the delayed previous scanline's demodulated chroma signal. If the signal is affected by phase distortion, then we should see Hanover bars - opposite hue errors from scanline to scanline:
The second picture shows the result I get when I use my "Full PAL" decoder --- averaging each scanline's demodulated chroma signal with the delayed previous scanline's demodulated chroma signal:
These results indicate to me that the PAL NES is just as susceptible to considerable phase shifts as the NTSC NES, but because the PAL system is designed to eliminate the effects of phase shifts, PAL televisions will display colors that are almost exactly the nominal hues minus 15.0 degrees.
Capturing regular television pictures and decoding them with my "Simple PAL" decoder exhibits only very slight Hanover bars, indicating little phase distortion:
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