When the source luma and chroma are properly filtered, it's hard to mess them up. The first full-bandwidth decoders were comb filters operating on non-filtered luma and chroma. They, of course, were imperfect.
TTFN, Mark Dale Kelly wrote:
Mark Wrote:If you envision the NTSC spectrum in three-dimensional space, luma is a large, central octahedron. Chroma is smaller octahedra orbiting it. It's only when you look at it in two dimensions that they appear to interfere, just as the moon (or any other satellite) would appear to occupy the same space as the earth when viewed in two dimensions.Very interesting analogy Mark and I'm winging it here!: Perhaps if one hypothesized these spectral octahedra as being somewhat akin to celestial objects and while not physically touching, had an energy source that did overlap, such as gravity. Such an energy source would create "parasitic" distortions. The encoders interleave the luma and chroma energy and in a perfect device, they would not occupy the same space and therefore would have no interaction. However, in reality, those energies encounter non linearity's which do create secondary IM energies and which do result in distortion artifacts. My more simple assumption (something that I can understand anyway!) is that these newer encoders not only better control the sources these distortions but also filter that energy which does exist - two dimensionally. Still pondering... Thanks, Dale-----Original Message----- From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Mark Schubin Sent: Saturday, January 13, 2007 11:43 AM To: opendtv@xxxxxxxxxxxxx Subject: [opendtv] Re: News: CEA FORECASTS CONSUMER ELECTRONICS REVENUE If you envision the NTSC spectrum in three-dimensional space, luma is a large, central octahedron. Chroma is smaller octahedra orbiting it. It's only when you look at it in two dimensions that they appear to interfere, just as the moon (or any other satellite) would appear to occupy the same space as the earth when viewed in two dimensions. TTFN, Mark Dale Kelly wrote:Must have trimmed down the sideband energy for those frequencies?-----Original Message----- From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Mark Schubin Sent: Saturday, January 13, 2007 11:24 AM To: opendtv@xxxxxxxxxxxxx Subject: [opendtv] Re: News: CEA FORECASTS CONSUMER ELECTRONICS REVENUE Dale Kelly wrote:Rather than using a bandpass filter I assume that the newer hardware allowed for notched filtering.It can be a lot fancier than that. The CDL Prism modulator,one of thefirst with full bandwidth, used two dimensional filtering of both luma and chroma to provide un-notched (but also non-interfering) full bandwidth of each. TTFN, Mark ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configurationsettings at FreeLists.org- By sending a message to: opendtv-request@xxxxxxxxxxxxx withthe word unsubscribe in the subject line.---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.----------------------------------------------------------------------You can UNSUBSCRIBE from the OpenDTV list in two ways:- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.
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