On Sat, 4 Mar 2000, Paul B. Webster VK2BZC wrote:

> Scott Dattalo wrote:
>
> > Hmm. Then what are the relative frequencies of these two wave forms:
> >
> >   +------------------------+                        +---
> >   |                        |                        |
> > --+                        +------------------------+
> >
> >   +------------------------+           +-----+      +---
> >   |                        |           |     |      |
> > --+                        +-----------+     +------+
> >
> > It's true that taken by themselves, the wave forms (or complex
> > waveforms as you've identified), are periodic and constant.
> > However, the first waveform has a lower frequency component not
> > present in the second. (Or said differently, the second wave form's
> > fundamental is twice the first's.)
>
>   Sorry, you have that backwards.  Both have the same fundamental
> frequency.  The second has a second harmonic frequency component not
> present in the first.  The fundamental amplitude is slightly lower.  It
> will be overall slightly better filtered by a given low-pass filter.

Of course, you're right Paul.

This:

  +------------------------+           +-----+      +---
  |                        |           |     |      |
--+                        +-----------+     +------+

Is not the same as:

  +------------+           +------------+           +---
  |            |           |            |           |
--+            +-----------+            +-----------+

The latter's fundamental frequency is twice the former's.



Scott