Embodiments of the invention may provide for a long delay generator for the spectrum sensing of cognitive radio systems. The long delay generator may include an Analog-to-Digital Converter (ADC), memory element, and Digital-to-Analog Converter (DAC). The memory element may utilize shift register bank or Random-Access Memory (RAM) cells. The long delay generator may provide for a selectable delay by digitizing the received signal, delaying the received signal in the digital domain, and reconstructing the delayed signal as an analog. The analog delayed signal may then be compared or otherwise correlated with the original input signal using an analog auto-correlation technique to determine whether a meaningful signal type has been identified or otherwise detected.