[time-nuts] OT - DC-10 gyros

[David]

If I did not go the microcontroller PWM route I would use a Johnson
counter (twisted ring counter) to directly generate three 120 degree
phases.  There is a good example here:

http://www.allaboutcircuits.com/vol_4/chpt_12/6.html

On Wed, 27 Mar 2013 21:55:32 -0400, Bob Camp <lists at rtty.us> wrote:

>Hi
>
>If three phase is actually needed, I'd suggest something like a cheap PIC with three PWM outputs. Fairly simple R/C's on the outputs should be plenty good enough to filter out any crud. Good frequency stability / accurate phase shift / cheap. What's not to like 
.
>
>Bob
>
>On Mar 27, 2013, at 9:44 PM, kb0ebg at juno.com wrote:
>
>> Bill Ezell;
>> 
>> Your Gyro may require 3 phase, 400 cps, 28 vac, Sine wave.
>> 
>> A simple "Buffered Phase Shift Oscillator" for 400 cps can create the Sine Wave.
>> https://www.circuitlab.com/circuit/h6v28g/buffered-phase-shift-oscillator/https://www.circuitlab.com/circuit/bakd83/phase-shift-oscillator-ii/You will need to add an AGC to the output for frequency stability.
>> A "3 Phase Generator" can create the 3 phase output.https://www.circuitlab.com/circuit/m4u5nw/3-phase-generator/ Add 3 Amplifiers (one for each phase) to reach voltage/power.
>> If the Gyro is directional, it will take several hours to stabilize.
>> 
>> Carl