On Sep 23, 3:02 pm, Brendan Gillatt wrote in:
How so? I am just asking extremely interesting questions about video technology.
I?ve tried painfully hard to answer my questions doing my own research
-- including reading information from books. I still haven?t found answers to my questions. That is why I am turning to NGs for assistance.
Is Quadrature Frequency Modulation used? What for?
AFAIK, Quadrature Amplitude Modulation uses a combo of AM and Phase-Shift-Keying.
So QFM would use a combination of FM and PSK. Would this decrease the bandwidth required for broadcasting FM luminance video signals?
I did a Google Search for ?Quadrature Frequency Modulation? on
None of those pages made any sense to me.
One major reason the luminance signals of television are broadcasted on an AM-carrier instead of an FM-carrier is because FM requires large amounts of bandwidth. Is there a way to use FM video without hogging so much bandwidth using QFM?
Does this mean that the FM-equivalents-of-QAM and Constellation Modulation can -- at least in theory -- be applied to FM video so that excessive bandwidth is not needed? If so, then what would be the minimum radio-frequency required to transmit the video signal? Is a 150 kHz radio-frequency sufficient to be an FM carrier for this video signal?
Constellation modulation is a type of AM. What?s the FM-equivalent of constellation modulation?
Has multiple-level QFM ever been used for video before?