Clock timing jitter refers to random perturbations in the sampling time in analog-to-digital converters (ADCs). The perturbations are caused by circuit imperfections in the sampling clock. This paper analyzes the effect of sampling clock jitter on the acquired samples in the midst of random noise. We propose low-complexity digital signal processing methods for estimating the jitter in real-time for direct downconversion receivers at high sampling rates. We also propose adaptive compensation methods for the jitter and analyze the performance of the proposed techniques in some detail as well as through simulations.