A frequency/timing measurement apparatus includes a reference source having a reference source output terminal. At least one target source has a target source output terminal. The at least one target source is communicatively coupled to the reference source. A frequency timing measurement block has a first input terminal electrically coupled to the reference source output terminal. A second input terminal is electrically coupled to the target source output terminal and at least one output terminal. The frequency timing measurement block is configured to perform a noise shaping technique to reduce measurement error attributable to a phase noise that is correlated between the reference source and the target source, and to provide a reduced correlated noise measurement at the at least one output terminal. A method to reduce correlated noise is also described.