open-source-silicon.dev

<@U017H530WC9>:  "working on low power miniature marine sensors and acoustic communications" :  I was briefly involved with a project on biosonar with Orincon and the NRL back in the late 1990s.  I'd be very interested in hearing about what you're doing.

Hi Tim, nice to meet you. I am a big fan of <http://opencircuitdesign.com|opencircuitdesign.com>!

My work is about low powered sensors in the marine environment. We are doing short range low power acoustic communications using narrowband techiques like FSK, and some broadband techniques like chirp spread spectrum and OFDM. Also low power techniques like pulse position modulation. Its for things like attaching time depth recorders to the backs of turtles at coral reefs in Australia and doing remote telemetry.

However, I'm here purely out of interest, not in any professional capacity.

I just think it would be nice (in theory!) to condense fairly small (e.g. 40mm * 15mm) circuit boards to a system on chip

I thought a way to start would be a simple, mostly digital design that took a baseband IQ stream at 10kHz sampling rate using SPI, interpolated it to 1MSample/s, frequency up converted it, and sent it to a simple R2R DAC. With some on chip buffer amplifiers to drive a transducer. That alone  would greatly condense our hardware.

I hope that gives you some idea of what we are working on :)

That sounds like a great project to run on sky130, to me.

<@U016EM8L91B> yes I agree, sky130 would be a good fit for this application. Right now I'm just looking into the tools and how to use them. I have organised with work to have 1 day a week until the end of the year to evaluate the tools and the open pdk, and make some kind of feasibility study or prototype design. We are very interested in getting the power consumption down as low as possible, particularly for the analog part. We may submit a design for the shuttle run, or we may not. I think the digital part of the design is straightforward; the analog part is more challenging. I am really looking forward to SPICE models being released to work on that, although I understand that's going to take some time. I've never designed a chip before so this is all a new (and exciting) experience!