Tai-Cheng Lee

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—A discrete-time analog echo canceller is described that reduces the echo in the front end of Gigabit Ethernet twisted-pair interfaces. Echo cancellation in the analog domain by means of four taps reduces the complexity of the digital echo canceller and crosstalk cancellers. Designed in a 0.4-m CMOS technology, the circuit employs an LMS algorithm to adapt(More)
—A stabilization technique is presented that relaxes the tradeoff between the settling speed and the magnitude of output sidebands in phase-locked frequency synthesizers. The method introduces a zero in the open-loop transfer function through the use of a discrete-time delay cell, obviating the need for resistors in the loop filter. A 2.4-GHz CMOS frequency(More)
—A discrete-time mixed-signal Gaussian frequency shift keying demodulator designed for a low intermediate frequency Bluetooth receiver performs FSK demodulation. Employing passive sampling and time-domain differentiation techniques, the demodulator performs quadrature demodulation while tolerating up to 200-kHz frequency offset. A distributed array of(More)
—A dual-operation-mode ring oscillator that employs dual-delay paths is presented. The two operation modes, referred to as the differential and common modes, have different output waveform characteristics and oscillation frequencies. A nonlinear model for the dual-delay-path ring oscillator and the analysis of the stability of each operation mode are(More)