Yep, I was doing some other MCU work and realised how easy it should be to implement. When I originally built the TX modulator I had the idea in mind, but I only just got around to trying it.
The “font” is only 5×5 which isn’t the most readable. The code itself supports 8 shift levels (bit-mapped into a byte), a text file defines the pattern. I also need to add predistortion to the modulation steps to compensate for the varactor non-linearity. I added a table to support shift predistortion, but I haven’t yet computed the values needed. I can pick them off my previous characterisation data for the modulator.
So very much WIP, but it is good to see the general idea working.
I’ll post the code once I finish the predistortion.
Hello Mark,
Yep, I was doing some other MCU work and realised how easy it should be to implement. When I originally built the TX modulator I had the idea in mind, but I only just got around to trying it.
The “font” is only 5×5 which isn’t the most readable. The code itself supports 8 shift levels (bit-mapped into a byte), a text file defines the pattern. I also need to add predistortion to the modulation steps to compensate for the varactor non-linearity. I added a table to support shift predistortion, but I haven’t yet computed the values needed. I can pick them off my previous characterisation data for the modulator.
So very much WIP, but it is good to see the general idea working.
I’ll post the code once I finish the predistortion.
Regards,
Alan VK2ZAY