Receiving Pulse-Code Modulation on AM radio at 3 Mhz?
Mike Gathergood (G4KFK) wrote:
Radium wrote:
My question: Will the received PCM audio signal remain noticeably
"clean" to the listener or will he/she notice the EMI, RFI, and
heterodynes affecting the audio?
I ask because I think -- but definitely don't know -- that because the
received signal is digital, it is less likely that the EMI, RFI, and
heterodynes would cause noticeable auditory disruptions when compared
to analog. Do I guess correct?
You guess correct, assuming that FEC is applied to the digital signal
before it is used to modulate the transmitter.
What if FEC is not used?
But you wouldn't do it that way anyway. Raw PCM is too bandwidth
inefficient. You'd use MPEG layer 2, or apt-X, or something like that
to reduce the bandwidth without noticeably degrading the audio quality.
You'd probably also multiplex several different channels (programmes)
together onto one RF carrier as well, to make better statistical use of
the RF bandwidth.
Cheers
Mike
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