Is it possible when using a sine looup table with the arduino to set a second analog input to control the amplitude or volume of a generated sinewave ?
I have analog input A0 set to control frequency from dc to a yet unknown frequency as im waiting for ny arduino to arrive, as i started off with the http://interface.khm.de/index.php/lab/experiments/arduino-dds-sinewave-generator/
and modified the code to put out three phases spaced 120 deg apart instead of just one.
For the project im working on i realized that i want a second analog input A1 set to change the amplitude/volume of the sinewave(after the inverter and output filters) from zero signal to full output.
This is for a variable frequency drive project to run either brushless dc or induction motors using sinewave commutation and i wish to use furrent feedback from the inverter to control the amplitude of the sinewave as part of a control loop for constant/overcurrent stuff and speed control.
However im not sure if changing the volume (like the volume control on a class d switching pwm audio amplifier) is possible when using a sine lookup table in software without reducing it down from the 256 possible values used.
If i have to use external means of adjusting the level and then comparator ic's to get the PWM back, then there wouldent be much point using a mcu at all, even though generating a three phase sinewave with adjustment capability from dc up to several kHz is almost impossible without a mcu of some kind.