Implementation of directional Doppler techniques using a digital signal processor

Three methods of deriving directional signals from phase quadrature Doppler signals, using digital techniques, are described. These are the phasing-filter technique, the Weaver receiver technique and the complex FFT. The basic theory behind the three methods is presented, together with the results of digital simulations. Each of the methods has been implemented in real time using a commercially available digital signal-processing board, and their relative processing times are compared. All the methods work well, and the decision to implement one or other in a specific application is likely to rest on secondary factors, such as the need to tape-record the time domain output.