The signal shaper transforms a triangle signal into a sine. The difference in our case from a real sine is given as a voltage. Voltage difference of 100mVpp is for a signal of 2.66Vpp which gives THD (total harmonic distorsion) of around 4%. Why is this important? Because is much easier to generate triangle signal of an adjustable frequency than a real sine. So the way to generate a sine is usually performed with sine shaping of a triangle signal.
