Random jitter (RJ) estimation based on Tail Fit algorithm are generally inaccurate in presence of deterministic components like the presence of sinusoidal jitter (SJ) and duty cycle distortion (DCD). Addition of deterministic jitter changes the standard deviation of the tail region of resulting jitter probability density function. A new methodology for random jitter estimation in presence of sinusoidal jitter and duty cycle distortion is presented. The method involves calculation of mathematical correction factor, which are derived and used to calculate the precise value of random jitter. The proposed methodology is validated by inducing known jitter sources in real channel simulator of ADS from Agilent. © 2013 IEEE.