sporniket / ideas

My backlog of ideas, organized as a bunch of issues
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Audio PCM to PDM conversion #14

Open sporniket opened 2 years ago

sporniket commented 2 years ago

Run the process at f(PDM) >> f(PCM)

At each step N

When

Then

Notes

sporniket commented 2 years ago

binary approximation :

Target Computation Binary Approximation
0.6x x - x>>2 - x>>3 - x>>5
0.16x x>>3 + x>>5 + x>>8
0.06x x>>4 - x>>9
powerpun commented 1 year ago

how about using FPGA to implement this?

sporniket commented 1 year ago

That's the plan

powerpun commented 1 year ago

there was a verilog there already: https://github.com/AUDIY/FPGA_PCM2DSD

powerpun commented 1 year ago

but I don't know how to evaluate the code's result for THD/group delay in an easy way.

sporniket commented 1 year ago

Thanks for the pointer, however it seems to be about doing the reverse (PDM to PCM) of what I want (PCM to PDM)

No idea about the THD.

This is for a core generating sound signal as PCM, and converting to PDM to use a single GPIO pin plugged to a speaker (with suitable circuitry)

powerpun commented 1 year ago

the verilog code I link is the PCM to DSD(PDM), not the reverse. please check the comment, which the input is PCM I2S output is DSD(PDM)

sporniket commented 1 year ago

yes, don't mind my previous comment not being what I want (I stroked it minutes after posting, when I had a better look).

Anyway thanks.

powerpun commented 1 year ago

it's fine. so what you wanna do? I wanna build this an ASIC but still need to evaluate this first in FPGA, I need help. I have some patents in audio playback. also low latency BT audio. (5ms)

sporniket commented 1 year ago

Then I think that I am not the right person for your project. This ticket is just a written down idea for a personnal, hobbyist-ish and opensource project with no commercial prospect whatsoever. And the expected time of beginning this part is undetermined -provided I need this part at all-.

I wish you good luck :)

powerpun commented 1 year ago

it's ok, and I got the C++ code for the conversation. so that I could translate c++ to verilog