Hi Katrina!It is all about a LFSR(4) sequence (I suppose) that (theoretically) has properties you are describing: normalized ACF(0) = 1, ACF(<>0) = 0. But it is only for bipolar sequence of infinit length. If the sequence is bipolar, length N then normalized ACF(<>0) = -1/N. If ACF(0) <> 1, then you have to normalize it. Predrag ----- Original Message ----- From: <> To: <> Sent: 2003. velja 22 20:24 Subject: [matlab] autocorrelation problem > Hi everyone, > > I need help in autocorrelation. I have generated a particular > sequence code, C of period 15 and need to find its autocorrelation. > I need to get the values at given lags from i = 0 to i = 15. For > example when i = 0, it's a perfect autocorrelation (no lag) so I > should get the peak value of the autocorrelation here. > Theoretically, this value should be equal to 1. But what I got was > more that. Subsequently, I got a constant value (which was lower > than the peak) when there is lag. Theoretically, I should be > getting a constant 0 value... > > What I did was multiply C by a cyclic shift of it for each lag. > What did I do wrong or forgot? Really need suggestions.... > > Thanks in advance! > Kat~ > > _____________________________________ > Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer. You need to do a "reply all" if you want your answer to be distributed to the entire group. > > _____________________________________ > About this discussion group: > > To Join: > > To Post: > > To Leave: > > Archives: http://www.yahoogroups.com/group/matlab > > More DSP-Related Groups: http://www.dsprelated.com/groups.php3 > > ">http://docs.yahoo.com/info/terms/ > > |