Abstract: In this paper, jitter-parameter measurement of digital Ultra-High-Definition-Video (UHDV) baseband signals is studied. We design a high-speed Serial-Digital-Interface (SDI) signal measurement method which adopts an improved dual-Dirac model to measure the jitter in the signal. Also we have designed a relevant hardware circuit to demodulate the clock signal in the SDI, which is then used as the measurement time reference. The method can accurately analyze different jitter components in SDI signals and make signal jitter measurement traceable to time-domain pulse waveform parameters by using the time-domain measurement method. The feasibility of this method was verified by experiments. The measurement results showed that this method has higher measurement accuracy than a direct spectrum measurement method.