Equal ripple approximation for envelope detection
Dennis M. Freeman · IEEE Transactions on Acoustics Speech and Signal Processing · 1978
We give a simplified derivation of the well-known equal ripple approximation to the modulus of a complex number as a linear combination of its real and imaginary parts. We also generalize the approximation to smaller sectors in phase, with corresponding smaller errors. We discuss the implementation of the generalized approximation, and indicate the number of computer operations required.