This paper evaluates the performance of spectrum sensing techniques like energy detector and matched filter in Cognitive Radio systems. To solve the problem of spectral detection two hypotheses H0 and H1, are considered. A statistic test over the received data is compared with a predetermined threshold, to check the availability of the channel and the accuracy of the detector. Hence, a detection probability (PD) and false alarm probability (PFA) are defined for a specific signal to noise ratio (SNR). A simulation is performed in Matlab and is validated on GNURadio using a board USRP N210 to detect frequency modulated (FM) signal at 100 MHz. The receiver operating characteristic (ROC) curves are used to illustrate the performance of binary classifier system when its discrimination threshold is modified. The matched filter gets a better performance than the energy detector under some characteristics and agrees with the requirements established to changes in PFA and noise power, besides has a higher measurement range (signal detection allows -25 dB SNR).