Re: frequency multiplexers
ayemen said:
thx
but what if all the signals have the same frequencies like voice for normal telephone from 0.3khz to 4khz and suppose i have 12 voice channels
thx
old phone techology and is not easy to make
this technology using lot of mixers, stable oscillators and
very sharp analogue filters (and give terrible
groupdelays - useless for highspeed mode in modem) and
transporting channel need absolut minimum 48 KHz bandwith.
for study this problem - you can using sound editing program
like 'coolwave' or simular and using modulation on 8 KHz carrier
and sharp band pass filtrering (4-8 KHz) on lower side band to
frekvenstranspond up 4 kHz.
next cannel modulated on 12 KHz carrier and filtering on 8-12 KHz,
next on 16 KHz etc.
remember using lower frequency than 1/2 of resulting
sampelrate - ie (48 KHz + 4 KHz (upper band on last cannel)) * 2 =
= 104 Ksampel/s
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study old telecomunictaions books from around 1970-1980 or so.
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better use digital soloution and high speed datalink