On Wed, 05 May 2004 23:39:08 +0100, Paul Burridge
wrote:

Hi,

I'll avoid posting a screen shot of this one since so many people seem
to have difficulty finding them on abse or can't get the group at all
from their servers.

Imagine a two-state, high/low (on/off) wave form; i.e., negligible
rise/fall times. Amplitude 5V. A bit like a square wave, in fact,
except that the on and off period appears *different* between one
cycle and the next and the next and so on. There's quite a bit of
variation (anything from one whole time division to up to seven divs
and all times between the two). There does appear to be an eventual
series repetition, but it's only noticeable after about 30 cycles. I'm
not sure how I've ended up with this, but would it be rich in odd and
even order harmonics and suitable for generating them for frequency
multiplication purposes, d'you think?

Thanks,
P.

What's the circuit supposed to do? What's the frequency? What is it
made of? What's on the inputs?

You probably screwed up as usual and need your betters to bail you
out.

- YD.

--
Remove HAT if replying by mail.

On 6 May 2004 21:11:59 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
That gives me an idea, Walter... How about I amplify the white noise
from a suitably noisy diode and feed it through a Schmidt or something
similar? What sort of harmonic richness would that give me?

I'm sorry, but I've not been keeping track of what kind of problem you're
trying to solve. It sure sounds like you're trying to reinvent some sort of
wheel here, though.

If you are trying to start with a noise source in order to generate a signal
at a specific, adjustable frequency, then surely you must consider that the
way to do that is to filter the noise source; and that the task of making a
good tuneable filter is no different than the task of making a good tuneable
oscillator. And starting with broadband noise is not generally a good
approach to getting something quiet.

I know. This is purely hypothetical. What sort of spectral range would
one get from this idea?
--

The BBC: licenced at public expense to spread lies.

On 6 May 2004 21:11:59 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
That gives me an idea, Walter... How about I amplify the white noise
from a suitably noisy diode and feed it through a Schmidt or something
similar? What sort of harmonic richness would that give me?

I'm sorry, but I've not been keeping track of what kind of problem you're
trying to solve. It sure sounds like you're trying to reinvent some sort of
wheel here, though.

If you are trying to start with a noise source in order to generate a signal
at a specific, adjustable frequency, then surely you must consider that the
way to do that is to filter the noise source; and that the task of making a
good tuneable filter is no different than the task of making a good tuneable
oscillator. And starting with broadband noise is not generally a good
approach to getting something quiet.

I know. This is purely hypothetical. What sort of spectral range would
one get from this idea?
--

The BBC: licenced at public expense to spread lies.

On Fri, 07 May 2004 00:27:43 -0300, YD wrote:

What's the circuit supposed to do? What's the frequency? What is it
made of? What's on the inputs?

You probably screwed up as usual and need your betters to bail you
out.

Damn! Forgot to tick the 'global' option in the Usenet filters list...

Plonk!
(again)
--

The BBC: licenced at public expense to spread lies.

On Fri, 07 May 2004 00:27:43 -0300, YD wrote:

What's the circuit supposed to do? What's the frequency? What is it
made of? What's on the inputs?

You probably screwed up as usual and need your betters to bail you
out.

Damn! Forgot to tick the 'global' option in the Usenet filters list...

Plonk!
(again)
--

The BBC: licenced at public expense to spread lies.

On 7 May 2004 17:11:36 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
On 6 May 2004 21:11:59 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
That gives me an idea, Walter... How about I amplify the white noise
from a suitably noisy diode and feed it through a Schmidt or something
similar? What sort of harmonic richness would that give me?
[...]

I know. This is purely hypothetical. What sort of spectral range would
one get from this idea?


Presumably that depends on how "suitably noisy" your diode is, and how fast
your Schmitt trigger is.

Here's a project for you: how can you describe the behavior of a
(real-world) Schmitt trigger in the frequency domain, that is, in terms of
how it affects a signal's frequency spectrum?

To put it technically, "they generate loads of harmonics" - a perfect
one presumably an infinite comb of harmonics? Am I near the mark?
--

The BBC: licenced at public expense to spread lies.

On 7 May 2004 17:11:36 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
On 6 May 2004 21:11:59 GMT, "Walter Harley"
wrote:

"Paul Burridge" wrote in message
.. .
That gives me an idea, Walter... How about I amplify the white noise
from a suitably noisy diode and feed it through a Schmidt or something
similar? What sort of harmonic richness would that give me?
[...]

I know. This is purely hypothetical. What sort of spectral range would
one get from this idea?


Presumably that depends on how "suitably noisy" your diode is, and how fast
your Schmitt trigger is.

Here's a project for you: how can you describe the behavior of a
(real-world) Schmitt trigger in the frequency domain, that is, in terms of
how it affects a signal's frequency spectrum?

To put it technically, "they generate loads of harmonics" - a perfect
one presumably an infinite comb of harmonics? Am I near the mark?
--

The BBC: licenced at public expense to spread lies.