Modeling phase noise in frequency dividers

A theory for modeling noise in frequency dividers and the measurements to support the theory are presented. The most complete measurements were made on ECL (emitter-coupled logic) dividers for which the primary noise contributions were from additive output noise and sampled additive input noise. Output phase power spectral density due to the latter varies as the square of the input frequency and is inversely proportion to the output frequency. The third most significant contributor was sampled output noise. A summary of available noise data is also given.<>