Talk:Amplitude-shift keying

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[edit] Applications

Can anyone fill in more details here? I'm thinking particularly in terms of applications.

An earlier version of the article said ASK was not widely used, but I wonder if that's really true. ASK appears to be a simpler form of QAM, and I believe QAM is used in lots of applications (broadcast television, for instance). However, I'm not too sure. Anyone? Simon 15:01, 21 Jan 2005 (UTC)

the ASK modulation is the base for most of the other more "refined" (and useful) modulations, but it is rarely used by itself since it would be a waste of channel amplitude. It is necessary to know it, to better understand the other modulations, but it is almost useless by itself. Alessio Damato 14:34, 21 September 2005 (UTC)

[edit] "Considerations" section

I have removed the "Considerations" section for the following reasons:

"ASK is the simplest kind of modulation that can be used to send data through a channel."

This is a subjective judgment; why is it necessarily harder to modulate amplitude than, say, phase or frequency?

"it can be used only when the signal-to-noise ratio is very high, because most of the signal is transmitted at reduced power, so it would be hard to recover."

This is wrong, and doesn't make any sense.

"it needs A/D converters working at a frequency that could be higher than necessary: for example, if the bandwidth between 100 and 101 MHz is used for the transmission, the spectrum of the signal will be only 1 MHz wide, but the A/D converter will need to work at 101*2 = 202 MHz. In QAM modulation, an A/D converter working at 2 MHz would be enough."

This is completely wrong, as in any practical application, down-mixing to baseband would be used. This is not mentioned anywhere in the article.

"Nevertheless, ASK modulation is very important because most of the other more complicated (and efficient) modulations can be expressed and studied in terms of ASK, such as QAM and PSK."

PSK cannot be analysed in terms of ASK, and beyond 4-QAM, there is little to be gained from viewing QAM as ASK.

Oli Filth 00:28, 5 September 2006 (UTC)