rfmmars:
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Using a "Y" cable can cause a problem with color because of the difference sometimes between the impedance of the two outputs.
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This makes sense so far...
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This does in some cases causes color smear or phase shift.
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You've lost me here - the Y cable is on a component out, which does not rely on phase shift for color information. If an impedance problem causes the levels to be different, it doesn't matter, because each Pb/Pr is affected in the same way. The only problem is the relative difference between Y+Px and Y itself. This can be corrected in software with a multiplication factor. Did you think I was talking about svideo?
tedkunich:
From the Connexant 878a datasheet:
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Digitized video needs to be band-limited in order to avoid aliasing artifacts.
Because the Fusion 878A samples the video data at 8 × Fsc (over twice the
normal rate), no filtering is required at the input to the A/Ds. The analog video
needs to be band-limited to 14.32 MHz in NTSC and 17.73 MHz in PAL/SECAM
mode. Normal video signals do not require additional external filtering. After
digitalization, the samples are digitally low-pass filtered and then decimated to
4 × Fsc. The response of the digital low pass filter is illustrated in Figure 3-3. The
digital low pass filter provides the digital bandwidth reduction to limit the video
to 6 MHz.
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Several graphs show -3dB @ 6MHz. That's pretty good! And the flash ADC is directly on the chip, so even the cheapest boards have the same excellent specs.
I have no doubt that what you were saying is valid for purely analog circuits, but digital oversampling filters can be almost perfect right to the edge of operation. There is also a "sharpness' register in the chip to let even higher frequencies through. Read a review of the Creative X-Fi soundcard, you will see +-.1dB all the way to Nyquist.
As for your other question, please see the thread in general discussion.