Cognitive radio is a technology that provides a promising new way to improve the efficiency of the use of the electromagnetic spectrum that available. Spectrum sensing helps in the detection of spectrum holes (unused channels of the band), and instantly move into vacant channels while avoiding occupied ones. A brief overview of the energy detection based spectrum sensing for cognitive cadio technology is introduced. An energy detector with baseband sampling for cognitive radio is presented with mathematical analyses for an additive white Gaussian noise (AWGN) channel. Practical implementa-tion issues on Texas Instruments TMS320C6713 floating point DSP board are presented. A new multiple antenna technique based energy detector is proposed. As well as, several algorithms for generating white noise are implemented.