How can we synthesize a wave having 1full cycle a normal sine wave and & for next full cycle inverted of 1st 1

Question

if suppose a sine wave starts from 0degree and completes its cycle in 360 degrees .... and for the next complete cycle it will start from where it have finished and that part of the second cycle has a shape of negative of a normal sine wave...
How can we synthesize such a wave form ...??

Answer 1

Switch the wave trhough a 180 degree phase shifter every other cycle. You can probably do this at radio frequencies with commercially available components but you can't do this at optical frequencies.