Erratum: Signal Generation via Nonlinear Interaction of Oppositely Directed Sonic Waves in Piezoelectric Semiconductors

When an ultrasonic wave propagates in a properly oriented piezoelectric semiconductor, it gives rise to both an electric field wave and a space‐charge wave. The rf signal developed across the crystal by the propagating wave is quite small. However, if one launches ultrasonic waves from the opposite ends of a properly oriented piezoelectric crystal so that the two waves travel toward each other, when the two waves meet, a rf signal of large amplitude, twice the frequency of the ultrasonic wave, will be developed across the crystal and the envelope (time function) of the double‐frequency rf signal represents the convolution integral between the two envelopes of the ultrasonic waves which were launched into the crystal from the opposite ends.