
ZRNA – Software-defined analog circuits - audionerd
https://zrna.org
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segfaultbuserr
> _We achieve this with the union of a field-programmable analog array (FPAA),
> an ARM processor and state-of-the-art firmware. An FPAA is similar in
> concept to a field-programmable gate array, but instead of logic elements,
> it is composed of analog elements: opamps, comparators, capacitors and
> switches. These fundamental elements are used to build higher level modules
> like filters, oscillators and gain stages._

Is it going to inspire a wave of FPAA hobbyist devboardvs and activities (just
like microcontroller and later FPGA)? If so, we are surely living in a great
time of computing.

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vvanders
The specs on the op amps aren't particularly impressive. The unity gain is
18Mhz which wouldn't be able to even keep up with a modern AVR
clock(16-20Mhz). You can find discrete parts with similar specs for sub-$1.

It's a neat idea and all but when it comes to the analog design space there is
a lot more variables to consider and constraints that drive them.

Your average FPGA on the other hand is able to synthesize multiple 8-bit
micros and benefits from wide parallelization, I don't see similar benefits
with this approach.

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analognoise
If you know nothing about circuits, this looks cool. I guess there's always
the hobby Blinkenlight crowd.

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crispyambulance
The concept of a field-programmable-ANALOG-array (FPAA) bubbles up to the
surface every once in a while. I think it's a neat idea with some interesting
use-cases.

Motorola had an FPAA product back in the 90's, but it never gained market
traction and was aimed primarily at education.

I wonder now that FPGA's have gotten so powerful and large if it isn't
possible to just simulate _specific_ analog parts and "wire" them together
into "analog circuits" to rapidly prototype analog designs? This would be
different from simulation on a computer because the simulated analog FPGA
circuit could actually be used, evaluated and tweaked in the field. Then, when
the design is mature one could realize it using actual analog components.

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bayesian_horse
I'm divided on this. It's hard for me to figure out what this hardware is
actually good for, and particularly in which use cases it beats FPGAs. As far
as I can see, FPGAs or DSP-cores in MCUs/processors seem to be the real
competitor, and the question will be at what sampling rate a DSP solution will
outperform whatever this ZRNA does.

And on top of that, the API looks quite understandable, so it may be easier to
use the ZRNA for a certain signal processing task than create a custom DSP
Core in Verilog or dig through MCU documentation. Though you could probably
make an API for generating verilog code for the Icestorm toolchain, which
would not require deep knowledge of digital design.

Other questions are bandwidth and sampling constraints. It seems to have at
least one ADC...

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tarcyanm
It's undoubtedly aimed at musical audio generation and signal processing. A
quick search will reveal the number of gotchas in implementing even a simple
alias-free (bandlimited interpolation) digital sawtooth wave, never mind
arbitrary wave tables. The rebirth of analog audio synths was partially driven
by the complex behaviors of real analog circuitry - particularly when you
account for saturation, hysteresis and other "imperfections" that don't occur
naturally in a digital simulation.

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_pmf_
Cypress PSoC does something similar. FPGA-light with some analog "wiring"
configurability.

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anfractuosity
I bought some of the Anadigm FPAAs a while ago, I need to get round to using
them, one thing to note though is they seem to use the discrete time style
circuit, so they actually switch at a high frequency between different
capacitors to generate a filter.

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jmpz
Can you say a little more about this? Would that negate some of the benefit of
this?

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urklang
The Anadigm FPAA implementation is built on switched-capacitor circuits. See
[https://en.wikipedia.org/wiki/Switched_capacitor](https://en.wikipedia.org/wiki/Switched_capacitor).
Alternative FPAA implementations exist, but are not yet commercially
available. See RASP from Georgia Tech:
[http://hasler.ece.gatech.edu/Published_papers/FPAA_Papers/](http://hasler.ece.gatech.edu/Published_papers/FPAA_Papers/).

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speps
It should support ChucK[1] for easy editing and prototyping, that would be a
great integration!

[1] [https://chuck.cs.princeton.edu/](https://chuck.cs.princeton.edu/)

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Troutmask1955
Super cool tech!

