A high-speed, on-chip implementation of Teager Kaiser operator for in-band interference rejection

The Teager-Kaiser (T-K) energy operator has been proposed in the digital signal processing community for applications such as speech processing and AM-FM demodulation. Recently, it has also been proposed for narrowband interference rejection in ultra wide band (UWB) impulse radio (TR) systems. However, sampling the signal and performing the energy operation in the digital domain is impractical for high frequency signals. In this paper we present an analog implementation of the Teager-Kaiser operator using LC-delay lines and balanced multipliers. The fabricated circuit consumes 2.6 mW and was measured to reject in-band interferers 17 times (~25 dB) larger the amplitude than the signal. The design works up to 4.5 GHz, for a signal bandwidth of 500 MHz-1.3 GHz. The design was also measured to work well with up to 500 Mbps BFSK demodulation and AM pulse demodulation.