Wish to generate a reference rectified sine

Hi
We need a unipolar train of half sines.....50Hz sine...so rectified thats 100Hz.
Also 1V pk...but variable to eg 0.9Vpk say.
Also, it doesnt have to supply any current...its just a reference for a switching power supply.
Do you know the best way? Low component count.

Is this as an engineering tool for development and test, or will it go into production?

How accurate (distortion level) does the sinewave need to be, and to what frequency accuracy?

A quasi-sinewave can be generated by double-integrating a square-wave.

this is for a production test tool

Is it too late to get a refund on your EE degree?

Several possibilities come to mind:

1 Simply rectify a 50Hz sine wave using a bunch of diodes.

2 Use a op-amp precision rectifier circuit. This will give better shape to the rectified sinewave "zero crossing" null.

3 Use a form of direct digital synthesis.
Store digitised values of a half sine wave into an EPROM (or similar), clock the values into a suitable D to A converter, pass the output of the DtoA through a low pass filter to remove the "steps" in the waveform caused by the digitisation process.

JimB

Can you use a function generator, or do you want it to be a stand-alone circuit?