Re: quadrature to voltage converter

Hello Tim,

Blech. You want to take a nice clean encoder signal and crap it up in the analog world just so you can crap it up more with an A to D conversion? Blech. I'd just get a bigger microprocessor. 

Hey, nothing against the anlog world, please...

Do this as an exercise in digital design:

                               .----------.
   A    .----.      .----.     |          |    ___       To ADC
  ------|D  Q|---o--|D  Q|-----|        up|---|___|---o---------
        |    |   |  |    |     |          |           |
     .--|>ck | .----|>ck |     |          |           |
     |  '----' | |  '----'     |          |    ___    |
     |         | '-------------|     ~down|---|___|---o
   B |  .----. |    .----.     |          |           |
  ---|--|D  Q|-|-o--|D  Q|-----|  some    |           |
     |  |    | | |  |    |     |  logic   |          ---
     o--|>ck | o----|>ck |     |          |          ---
     |  '----' | |  '----'     |          |           |
     |         | '-------------|          |           |
     |         |               |          |          ===
  ---o---------'               '----------'          GND
  clock
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de


Ok, can't do ASCII art so I'll describe an alternative:

Replace the cap with a resistor, delete the digital stuff and run A and B directly into the two horizontal resistors but make these of different value. Now there will be four distinct voltage levels coming out. That allows to resolve from the ADC value the status of A as well as B at any time. Basically you now have a 2bit poor man's DAC that feeds the ADC input.

Regards, Joerg

http://www.analogconsultants.com
.