[nrv-hams] Sine Wave Morse Code Oscillator Circuit Needed

[Alvin P. Schmitt]

I believe you need the first derivative
https://en.wikipedia.org/wiki/Differentiator

I could model the one with the op amp on LTspice with a square wave
input  if you like

On Thu, Jul 11, 2024 at 8:25 AM Cam Coble <cam at doubleclickdata.com> wrote:
>
> Not as easy as I thought...
>
> OK, there are *plenty* of circuits out there making use of 555 timers and
> other methods that create square waves, and I can certainly filter the
> output to make it sound a little better, but I'm reaching out to find if
> anyone has a link or schematic for a nice sine wave oscillator for CW
> practice.
>
> If there is a good kit, send that link too, but I prefer to scratch build.
> This may be something we use for a Winter Build Project if I get the time.
>
> My last attempt was using a side-tone generator from the W1FB's QRP
> Notebook (pp145 lower left circuit) along with an LC filter. I evidently
> need practice with my filters as It looks like I only got the start of the
> square wave smoothed out. This helps, but there's nothing like the sound of
> a real sine wave.
>
> Target is 700 Hz (or variable), and at least headphone output levels.
> Bonus for some debouncing for use with a Bug.
>
> Help!!!
>
> 73
> --
> Cam, W4XXV
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