sftrans Transform band edges of a prototype filter (cutoff at W=1) represented in s-plane zero-pole-gain form (Frequency Transformation in Analog domain). [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop) [Sz, Sp] = sftrans (Sz, Sp, Sg, W, stop) [Sz] = sftrans (Sz, Sp, Sg, W, stop) Sz: Zeros. Sp: Poles. Sg: Gain. W: Edge of target filter. stop: True(%T or 1) for high pass and band stop filters or false (%F or 0) for low pass and band pass filters. Given a low pass filter represented by poles and zeros in the splane, can be converted into a low pass (having diffrent cutoff frequency), high pass, band pass, band stop. by transforming each of the poles and zeros individually. Sonu Sharma, RGIT Mumbai (fellow at FOSSEE, IIT Bombay)