[Orion] Re: A test of Orion's external CW keying

[Martin Ewing <martin@aa6e.net>]

Sinisa's result is not too surprising to me, since it seems that just about 
every control function in the Orion is handled through the "Dragonball" 
processor.  This is cost effective, but it leads to strange artifacts, such as 
he investigated.

Here's an experiment you can try.  With transmitter disabled (or with dummy 
load), send some CW with the internal keyer and spin the tuning dial at the same 
time.  You will see the sending slow down as the CPU is busy tracking the 
frequency.  This shows that CW keying is handled as a "process" in the CPU, 
subject to all the timing jitter and pre-emption you might expect from a 2.7 
MIPS processor that's also managing the VFOs, the LCD, the DSP processors, the 
serial port, etc.

It is not "wrong" to implement keying through a CPU, but you need to use 
real-time OS design principles - guaranteeing proper maximum latency for each 
task, etc.

All to save a couple of dollars on an analog keyer chip...

73 - Martin

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