We designed ultra-low noise regenerative divider-by-2 circuits that operate at input frequencies of 20 MHz and 10 MHz. We achieved residual output-referred single-sideband phase noise below -162 dBc/Hz at 10 Hz offset for a single divider at these frequencies. In order to measure such a low noise we also built a cross-spectrum measurement system that has a noise floor of -175 dBc/Hz at 10 Hz offset from a 5 MHz and 10 MHz carrier. The low noise of the divider and the measurement system are achieved by use of custom-built mixers/phase detectors that use 2N2222A bipolar junction transistors (BJTs) in a conventional double balanced diode ring.
Citation: IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
Pub Type: Journals
Frequency synthesis, Mixer, Phase noise, Regenerative divider