Hello,

I'm working on a demo for a Verlog/FPGA class I've been giving internally.  Have a simple microphone/speaker hat (MagPi Voice Hat) that is wired into an FPGA board.  The chip is a Xilinx Zynq XC7Z020 on a PYNQ board.  For purposes of the class I'm running it tethered and just using the programmable fabric and not the processor.  Yes, I know I'm leaving 98% of the functionality on the floor but the focus for the class is Verilog and FPGA logic and it has worked out well for that.

So, I want to have a little demo with the speaker interface.  For that it would be cool to have a "voice" that I could step through some notes.  A wave table lookup is possible but for the class I really want something simple.  Anyone know of a simple voice, something better than a sinewave or sawtooth I could step through?

Looking for ideas.

Thanks in advance,

Mark Napier

Hi Mark,

what about a chirp (sine sweep from a certain low frequency up to one (or some) octave higher and then down again, while increasing and decreasing loudness  (like a whistle).
Sounds interesting, is mathematically describable and has probably most of the interesting effects for mainpulations like amplitude correction, filtering, spectral analysis etc.

Bernhard

Hey Bernhard,

Good idea.  I can do that with a phase accumulator and a look up table.

Mark