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5 MHz Phase Detector With Low Residual Flicker



Corey A. Barnes, Archita Hati, Craig W. Nelson, David A. Howe


The measurement of close-to carrier phase modulation (PM) noise of state-of-the-art oscillators is always challenging. Quite often the residual noise of the phase detector used in these measurements is the source of difficulty. In particular at Fourier offset frequencies between 5 and 100 Hz, oscillator noise has a slope of f- -3 and may be lower than the mixer noise floor which follows a slope of f- -1. A conventional double balanced mixer (DBM) using 2N2222A transistors as the non-linear components of a diode ring is constructed for use as a phase detector. Residual single-sideband PM noise measurements at 5 MHz for this device have shown an extremely low flicker noise floor of L(10 Hz) = -165 dBc/Hz. The low noise floor of this mixer makes the device ideal for use as a detector for PM noise measurement systems. Implementing this mixer design in a dual-channel measurement system, a cross-correlated PM noise floor of better then L(10Hz) = -170 dBc/Hz is expected. These features set this DBM design apart from other mixers used for phase detection at 5 MHz.
Electronics Letters


Flicker noise, mixers, phase detector, phase noise


Barnes, C. , Hati, A. , Nelson, C. and Howe, D. (2011), 5 MHz Phase Detector With Low Residual Flicker, Electronics Letters, [online], (Accessed April 24, 2024)
Created September 15, 2011, Updated February 19, 2017