I read in sci.electronics.design that Tim Wescott
wrote (in .
com) about 'Extracting the 5th Harmonic', on Fri, 12 Mar 2004:

Yes, it's pronounced "sink", and it's quite common in signal processing.
You define it as being the _limit_ of sin(x)/x as x - 0 because
otherwise it's undefined at zero, and all the mathematicians in the
crowd will curse at you for being yet another engineer who's treating
math so casually.

I don't fear the wrath of any mathematician. The limit is very firmly
established as = 1 at a quite elementary level. Just consider the
expansion of sin(x) = x - (x^3)/3! +.....

Of course, it can be established more rigorously, but there is nothing
wrong with the series expansion AFAIK.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk