Bandwidth-efficient recursive pth-order equalization for correcting baseband distortion in parametric loudspeakers

Kelvin Chee-Mun Lee, Woon-Seng Gan
2006 IEEE Transactions on Audio, Speech, and Language Processing  
A bandwidth-efficient recursive implementation of th-order equalization is developed in order to correct the inherent baseband distortion in parametric loudspeakers. Assuming that the nonlinear system is largely quadratic, a substitution of it can be made by using an analytic pair of all-pass sections cascaded with a squared magnitude block. The all-pass sections comprise of a delay block and an approximate linear-phase infinite impulse response (IIR) Hilbert transformer to give a Hilbert
more » ... orm pair. In this way, the distortion terms produced are due to the difference frequencies only and therefore within the bandwidth of the original input signal. When used together with a single-sideband (SSB) amplitude modulation (SSB-AM) scheme, this new method allows the equalized SSB output signal to be faithfully reproduced to correct the distortion. Simulation results in this paper show that the new method is able to suppress residual in-band distortion components by 70 dB or lower.
doi:10.1109/tsa.2005.855830 fatcat:wvwblsrl2ze43gktnqjkghp5hi