Talk:Audio frequency-shift keying

This page should explain the difference between coherent and non-coherent AFSK. It might also cover the two common demodulation methods, FM/PLL and tuned-filter.

I'll get around to adding this eventually, if no one else does first.

Simon 15:16, 18 Jan 2005 (UTC)

Oh, and some diagrams would be nice, too.

Simon 15:18, 18 Jan 2005 (UTC)

Wish you could elaborate more examples on application on Frequency Shift Keying. -SHAIAN & MARSHA-

ASFK is another subject than FSK. One is a modulation to transmit signal over radio frequencies, while the other is a manner to join different audio frequencies as used in telephony to transmit information.

Why does this article exist??

There is absolutely nothing (mathematically) that distinguishes audio FSK from "normal" FSK, so why does this article exist? What's next, "Audio ASK" and "Audio PSK" articles? Oli Filth 20:19, 27 September 2006 (UTC)

Baseband?!

Why does this article claim AFSK is baseband? If this were so, the data rate would change depending on the data being sent. As far as my understanding goes, if this were a baseband modulation technique, the frequency of the signal would determine the data transfer rate. As far as I can understand from the article, this is not the case and AFSK is identical to FSK in all regards, other than the frequency in use. This doesn't make sense. If it were operating at baseband, the data rate would change depending on the current frequency being transmitted, and the signal would be difficult (impossible?) to lock at the receiver. Please clarify or remove this from the article. --Ktims 00:29, 24 October 2006 (UTC)

While I would agree that there's essentially nothing that distinguishes AFSK from FSK (see my point above), I'm not sure I understand when you say "the data rate would change depending on the data being sent" and "the frequency of the signal would determine the data transfer rate". The centre frequencies in use are determined by the oscillators, and the bandwidth is proportional to the data rate, as with most modulation schemes, baseband or passband.

I guess one could consider "AFSK" as baseband, because in general it's likely that its bandwidth will be of the same order of magnitude as the upper centre frequency. (Also, from an RF comms point of view, there's no up-mixing involved, but that doesn't necessarily imply it's baseband.)

Oli Filth 07:45, 24 October 2006 (UTC)