Hello
I need a sine wave generator capable of :
50 Hz frequency output (precision not that important)
output voltage stability: +/-0.03 % (output voltage ~3V dc)
What topology do you recommend in order to achieve such high stability of the sinusoidal output voltage?
You said 3V dc, so I wasn't sure what you were referring to.
For such stability you would likely need a negative feedback AGC loop to regulate the voltage.
You could use a phase-shift or Bubba oscillator to generate the sinewave (do you have any distortion requirements?).
You could use a precision rectifier on the output to convert the AC to a DC average voltage.
This DC average could be fed into a subtractor circuit along with the voltage from an accurate reference voltage source.
The error difference from the subtractor could be integrated (to minimize offset error) and fed to an analog multiplier, such as an AD623, in the oscillator feedback loop to control the output voltage.
I believe that a digital (DDS) sine generator is the most simple way to generate a frequency and amplitude stable sine, e.g. AD9837.
An analog solution has been suggested by crutschow. For the gain control element you don't necessarily need a precision multiplier, precise level measurement and high gain PI controller are the essential points to achieve the intended accuracy.
I believe that a digital (DDS) sine generator is the most simple way to generate a frequency and amplitude stable sine, e.g. AD9837.
An analog solution has been suggested by crutschow. For the gain control element you don't necessarily need a precision multiplier, precise level measurement and high gain PI controller are the essential points to achieve the intended accuracy.