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

To: tentec@contesting.com, orion@contesting.com
Subject: [Orion] Re: A test of Orion's external CW keying
From: Martin Ewing <martin@aa6e.net>
Date: Fri, 27 Feb 2004 11:20:34 -0500
List-post: <mailto:orion@contesting.com>
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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