312 a and cognitive 313 are synchronized the plot 600 shows how d changes with respect to the delay between primary user 39 s signal and the reference chirp signal for example if the primary user 39 s signal is delayed by 0 5t seconds where t is the bit period d drops by 25 nonetheless the system is tolerant to delay up to 0 25t seconds in both sinr cases shown moreover additional research has shown that in the event when the primary and cognitive networks are not synchronized d is dependent on the overlapping duration between the chirp duration tc and the bit duration tb therefore even in worst case scenarios when the overlapping between the first chirp duration and the carrier bit is not enough the consecutive overlapping should be enough to make a better decision this may lead to the conclusion that the observation interval must be at least twice as much as the chirp signal period to avoid this drawback with respect to temporal resolution this resolution is obtained by the process of correlation but in this case the received chirp is correlated in the time domain with its mathematical conjugate this procedure is distinguished from the spectral sensing in that the correlation is with the conjugate not the signal itself moreover this is called cross correlation not autocorrelation actually when the signal is correlated with any other signal apart from itself this is called cross correlation as shown in fig8 the reference chirp 305 a.