[sdiy] Screwing with Square Waves

[Donald Tillman]

On Oct 31, 2013, at 4:30 PM, John Marshall <wa7bsr at gmail.com> wrote:

> I really liked the presentation.

Thanks!

>  Shouldn't the square wave formula be 1/3 + 1/5 + 1/7 ....I see 13 + 15 + 17 .....?

What browser are you using?  The equations are written in MATHML, an HTML extension for displaying equations nice.  Perhaps your browser isn't handling MATHML.

(Computer people think they're such brainiacs, but HTML has never addressed even the simplest equations.  Early on I tried laying them out in totally awkward HTML, then I gave up on that and wrote equations out in LaTEX, grabbed the generated image, and plopped that in.  Now it's MATHML, which is reasonable.)


> What is the harmonic spectrum of a full wave rectified sine wave?

I think it's:

  y = sum [ (1/(i^2 - 0.25)) cos(iwt) ]

For all even i.  And add a DC bias.


> Speaking of not found in nature: an infinite series of even harmonics.

Well, there's the full wave rectified sine wave.  :-)

Actually, a half wave rectified sine wave.

  -- Don

--
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com