Timing jitter in PAM, ASK, and QAM for a bandlimiting scheme

Timing jitter in M-PAM, M-ASK and M²-QAM with AWGN is calculated for a cosine roll-off bandlimiting scheme applying a newly derived closed-form representation in the frequency domain of the jitter power spectral density (jitter PSD). Jitter PSD consists of SS, SN, and NN components. Each component of jitter variance is obtained by integrating the corresponding jitter PSD over a finite frequency domain in a bandlimiting scheme. The total jitter variance is obtained as the sum of the three components. The dependencies of the calculated jitter variance on the system parameters, i.e., SNR, ¿, alphabet size, M, transmission scheme, PLL normalized noise bandwidth, b_L, and roll-off factor, ¿, are evaluated. Specifically, the SS component increases with increasing M. However, this increase is limited within a finite range. Since the SN and NN components are independent of M, the dependence of the total jitter variance on M is small. At low and medium SNRs, the total jitter variance is independent of M. At high SNRs, the total jitter variance increases with increasing M, but the increase is rather small when M is greater than 4. Calculated values of the SS, SN, and NN components of jitter variance in QAM are tabulated. The numerical values in QAM can be used to determine the numerical values in PAM and ASK.