A fixed-point implementation of the unnormalized least-squares lattice using scaled-integer arithmetic

The unnormalized least-squares lattice algorithm is modified for fixed-point hardware by appropriate scaling of the cross-correlation, covariance, and likelihood parameters. The scaling reveals the dependence of the unnormalized parameter magnitudes on the number of error signal observations used in their respective updates. Comparing fixed-point and floating-point simulations shows no significant loss of precision in the estimated PARCOR coefficients in the fixed-point environment with scaled parameters. Scaling requires seven more multiplies per lattice stage but provides a least-squares lattice algorithm suitable for a wide variety of fast low-power signal processing chips without square-root normalization.