On Mon Sep 01, 2008 at 10:41:29PM +0100, Andy Farnell wrote: > > > > Single sideband modulation. > > It comes from radio culture really. In the modulation schemes for analogue > broadcast you havethe same spectral model with radio waves as we > use for sound synthesis. But using up more bandwidth by having two sidebands > is less desirable if you want to squeeze more channels into the same spectrum, > so SSB was devised to minimise interference between stations.
the carrier is a really loud sine, relative to the other material . reduced carrier was projected to occur (in the 70s/80s or so), with enough power for a phase reference under typical conditions.. i think -15db or so so broadcasting the carrier and the duplicate sidebands saves a lot of energy ( in addition to spectrum ) its how Lou from Barcelona running 1.7kW sounds as good as Radio Exterior Espana running 250 kW or something insane > > The tradeoff is that fewer sidebands mean less information is carried by > the signal. nope the sidebands are typically identical but frequency mirrored the main tradeoff is finding the beat frequency, without a carrier. to get the right pitch base for the spectral information. not only do you lose the phase reference, you lose the frequency reference! > Anyone know any novel or unusual patches for SSB. Presumably, for a single > frequency > you need only a fixed delay. im thinking about getting a QS1R and using PD for demodulation should i? _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
