A balanced injection-locked, phase-locked loop array for spectrum analysis

A balanced ILPLL array is demonstrated to provide an orthogonal basis to estimate the frequency and power of an unknown in-band signal. The opposite loop gains cause the VCOs to be tuned in opposite directions around the injected frequency. The injection frequency is then the average of the two detuned frequencies and the injected amplitude is proportional to the difference in tuning voltages. Low power consumption can be achieved by integrating the balanced ILPLL array on chip.