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Re: antennae

This am thing will work with say a delta 66 card(24bit 96khz)? How is that possible when your maximum playback can be 96 khz (which will play frequencies of at most 48khz) not anywhere close to 550kz that you would need as carrier. Maybe I am missing something and I will be the first to admit it but that doesn't make sense to me.

ben nevile writes: 

i'm interested in shortrange radio broadcast (within a 20ft.x20ft.
room)...going to try to do all the encoding in software


AM is easy, just multiply your (mono) audio signal by a carrier wave
somewhere between 550 and 1300kHz. if your carrier is at frequency f you
will need to filter out all frequencies above nyquist-f if you want to avoid
aliasing. (nyquist is half of your sampling rate: 22kHz for most sound
cards.)

the carrier you need to generate an FM signal can't be generated by a stock
audio card because it's in the MHz region. I don't know anything about
antennae but I'm sure there are schematics galore at your googletips.

bonne chance
b


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