--- Patrick Lindecker <[EMAIL PROTECTED]> wrote:
> Hello Martin,
>
> 8 bit or 16 bits is not the problem, only the
> algorihm used or the hardware
> processing makes the difference. One of the problem
> is the automatic
> determination of the speed. Did the old Pakrat
> determines the CW speed
> itself or do you have to enter it? In the same order
> of ideas, do you have
> to determine the threshold level or is it automatic?
>
> A comparizon between the old Pakrat and a modern
> software (Hamscope or
> Multipsk) with the same CW signal would be
> interesting and if really the old
> Pakrat is much better, it would be very interesting
> to know more about it
> and why it is better.
>
> 73
> Patrick
Some 15 years ago I did some experimenting, and ported
a program from an RSGB book (Computers for the Radio
Amateur or something alike) to my C-64 to decode morse
code.
I used a NE567 as tone decoder that fed one bit of the
C-64 "serial port".
The algorithm used the bit duration as selection
criteria. One bit, one dit, longer than one bit, a
dash.
The program used a sort of running average to
determine the speed. It was very slow "to train". A
longer averaging time meant more stable
decoding....once it achieved "speed sync". The program
derived the bit duration from that, and derived the
dot or dash criteria from it.
The PK-232 uses its hardware filters as decoders, it
has a threshold level on the front panel and is a good
morse decoder.
But so far, the ear is better decoder than hardware.
At least, unless someone can devise a neural network
to decode morse.
Morse code was created around 1830, and was not meant
to be machine decoded. Nowadays, better codes exist,
eg., Varicode. It is a dilemma, Morse allows simpler
transmitters and meant for human reception. Better
codes do exist, but are meant for machine transmission
and reception, and require more complex transmitters
and receivers.
For morse contesting, I prefer an iambic keyer or a PC
running CT and reception by ear, as contests are meant
to be. Anything else does not work...feed a pileup to
a machine morse decoder and get ready to see only
gibberish....
If the PK-232 is better as a decoder is possibly
because such a hardware decoder may achieve
effectively smaller duration cycles to compare the
duration of a "bit" than a PC with the OS and
multitasking / multithreading burden. It is only my
guess, and might as well be wrong.
73 de Jose, CO2JA
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