Simple and very easy to use software ,a good way to learn DSP. sketch and analyze the dft of sinusoids,pole-zero placements, magnitude plot ,phase plot, frequency response of a digital filter ( even no need to install) just click the file and enter the required parameters and then press show -Simple and　 very easy to use software ,a　good　way to learn DSP. sketch and　analyze the dft of　sinusoids,pole-zero placements, magnitude　plot ,phase plot, frequency response　of a　digital filter ( even no need to install) just click the file and　enter　the required parameters and　then press show