[CW] Good Sounding Sidetone or Code Practice Oscillator Kit

[pa0wv]

Dave,

I have nothing for sale. hi

I just read the story on the website of the announced (by you) kit 
seller, I noticed a number of bloops, and I reacted on that. Nothing else.

Furthermore I published the spectrum of the signal of the distributed 
wav file of the kitseller and of the demosignal that I provided with the 
same leading and trailing edge; slope cosine squared.

When you increase pitch, that has nothing to do with the slope of 18 ms
(mS means millisiemens, what you probably call millimho) the right way 
to write millisecond  by international agreed standards is ms)

The carrier (here: pitch of the audio) has nothing to do with the 
bandwidth of the signal. When you make your signal at a higher pitch 
with the same slope the spectrum is shifted upwards in audio frequency 
but the bandwidth keeps being  the same. And so 33 wpm is still the max 
speed even at 1200 Hz carrier pitch, because the leading and trailing 
edge of each 18 ms meet each other in that case  with that speed in wpm.


The number of sinewaves of the carrier in a dit is not of influence on 
the bandwidth of the spectrum. The slope (leading and trailing edge) and 
the construction of the slope is important.


I forgot to mention the point that the logarithmic sensitivity of the 
ear has in my humble opinion nothing to do with the slope construction 
of 7 times 3 dB increments, as the kitseller posted on his website, 
because just as with AGC the ear has to be slower in regulating the 
sensitivity then the envelope of any signal you detect with the ear, 
otherwise you should compress the audio signal amplitude variations.

When the kitseller thinks that a phasejump should have any negative 
influence  at the start of his dit, he has to accept a phasejump at the 
stop of the dit, unless the speed is such that an integer number of half 
waves of the pich (carrier) is just equal in time to the length of one dit.

When he uses 1% resistors and the smallest is 1 % larger then nominal 
and all the other 7 resistors are 1% smaller then nominal it is easy to 
see that a step of value 127 to 128 (01111111 to 10000000 binary) yields 
a spike of 4% of the sinewave amplitude.

The spectrum (= Fourier transform) of the demo18ms.wav that I provided 
and the signal the kitseller provided are available on my website as 
announced in a previous posting.

73 Wim PA0WV