Rectification is a type of distortion effect where the negative amplitude values of a signal are distorted in different ways. For full-wave rectification, the negative amplitude values are changed to the identical positive amplitude values.
There are several ways full-wave rectification can be created in computer code. First, the absolute value function from mathematics can be used to process the individual samples of a signal. Second, a conditional statement can be used to invert the polarity of the negative samples in a signal without processing the positive samples.
The absolute-value function can be described mathematically as an even function. Therefore, the harmonics resulting from full-wave rectification will be even multiples of the frequencies in the input signal.
This type of distortion is related to, but different from, half-wave rectification.