Correlation coefficient of column data - fluctuating values

Hi,

I am obtaining correlation coefficients of two sets of column data - I am not using corrcoef or any function per se, I just wrote my own code to compute the value for the Pearson correlation coefficient and it works as it's supposed to.

I have 463 (Ch1) x 500 (Ch2) datasets. I obtain all correlation values of Ch1(1) with Ch2(1:500), then Ch1(2) with Ch2(1:500), and so on. This yields a 2D array of correlation values of which I choose the maximum value of correlation of each row (yielding 463 values in total).

However, I seems that I am getting fluctuations in the correlation values, almost like an inverse sawtooth function - can anyone advise me on why this would happen? I would appreciate it.

Kista