[sdiy] FM Synth Designs

patchell patchell at silcom.com
Tue Aug 13 16:22:22 CEST 2002

    This is correct...as far as I know...in fact, I was under the impression
that Yamaha had a patent to cover this...back in those days, putting a hardware
multiplier in silicon was very expensive.

    Nowadays...heck, you can put several 16x16 multipliers in an FPGA that only
costs a few dollars (well, maybe a slight exageration...but close).

    Implementing an FM synth engine in an FPGA these days would be very simple.
I would like to do this myself, but, there aren't enough hours in a day.

Colin Fraser wrote:

> My understanding was that the DX7 implemented 'multiplication' to vary the
> amplitude of it's operators by adding two sine waves together with a phase
> difference proportional to the required amplitude, instead of acutally
> multiplying the wave data by the amplitude value.
> This would mean changing the waveforms wasn't viable.
> Later units with a choice of waveforms used hardware multiplication.
> Could be wrong...
> Colin f

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