For anyone that needs a little refresher course, the sine function gives the ratio of the opposite side of a given Angle in a right triangle to the hypotenuse.

This paper designs a Lissajous Figures signal generator which can generate sine wave with different ratio of frequency, By utilizing oscillograph, all kinds of stable diagram can be shown.

A practicable solution to the angle-digital conversion of synchro is provided, which includes cut section coding for the ratio of sine to cosine and sampling on double peak value.