An adaptive broadband BiCMOS active spur canceller

An active interference cancellation system is presented in BiCMOS 8HP capable of eliminating undesired signals resulting from an on-chip clock whose fundamental and/or harmonics couple into a receiver path. The cancellation system is capable of eliminating undesired clock fundamentals from 6 - 10 GHz and its harmonics up to 30 GHz. By modeling the coupling channel, the system recovers receiver sensitivity and is independent of the aggressing clock rate and amplitude fluctuations. A variable phase rotator, comb generator, and an amplitude modulator are used to achieve the cancellation. The use of a comb generator in a cancellation system is novel and enables harmonic cancellation. Over 25 dB of cancellation for an aggressing clock and its harmonics have been achieved. A series-to-parallel bus that communicates with all system sub-blocks provides a healing aspect to the system. The total power consumption of the canceller system is 71 mW.