Here’s this week’s development updates for bFunc, the open source function generator I’m developing. Each day’s entry represents an hour’s work - the hour before I start work on my real job every weekday morning.

If you’d like to buy a board to try, you can purchase one over on Gumroad!

If you're new here, and want to understand what this whole "bFunc" thing is and what it's about, you can take a look at the design doc for this project.

If you're not that into philosophy, or just impatient to check out source files, all of my hardware and software source files are on GitHub. Check ‘em out!

This Week's Progress: Researching a bunch of components for the next rev - output opamps, filter topologies, some boost regulators, etc…

May 19, 2020

  • There’s such a thing as integrated, dual power supply modules. Whoa.

May 18, 2020

May 13, 2020

  • I had found [Craig]’s post on Hackaday reviewing the MHS5200-A function generator but I didn’t realize he’d gone to the next level and fixed some parts of the design to make it work better. Super cool!
    • Swapping out the output driver opamp for a higher slew rate model is instructive!
    • The notes on the elliptic filter redesign are also really neat!

May 12, 2020

  • Wrote some target specs for next revision - bFunc - Rev2.0 - Specs
  • Made a set of quick sims for the output stages of the next rev
    • Elliptic Filter - Step Response to 10ns rising edge
    • Elliptic Filter - Bode Plot
    • Output Driver - AD8065
  • Started hardware_rev2!!
    • Starting with DDS sheet
    • Changed over to AD9834
    • Started to add in features
    • To-Do: Double check all the decoupling capacitors
    • To-Do: Update Crystal (need 75MHz)
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