This paper describes two algorithms for pitch determination of speech signals. One is an extensively modified Tucker and Bates algorithm which extracts features of the signal in the time domain and uses these to estimate the pitch period, and the other is a modified SIFT algorithm involving short-term autocorrelation of the LPC residual signal. For a real-time implementation, the modified Tucker-Bates algorithm was written in assembly language for a single chip DSP device, the Motorola DSP56001. Details of the algorithm and its implementation are explained and its performance discussed.