Title :
A Low-Power Magnitude Detector for Analysis of Transient-Rich Signals
Author :
Rumberg, Brandon ; Graham, David W.
Author_Institution :
Lane Dept. of Comput. Sci. & Electr. Eng., West Virginia Univ., Morgantown, WV, USA
fDate :
3/1/2012 12:00:00 AM
Abstract :
Magnitude detection, such as envelope detection or RMS estimation, is needed for many low-power signal-analysis applications. In such applications, the temporal accuracy of the magnitude detector is as important as its amplitude accuracy. We present a low-power audio-frequency magnitude detector that simultaneously achieves both high temporal accuracy and high amplitude accuracy. This performance is achieved by rectifying the signal with a high-ripple peak detector and then averaging this rectified signal with an adaptive-time-constant filter. The time constant of this filter decreases with increasing amplitude, enabling the filter to quickly respond on a short time scale to transients, while steady-state ripple is averaged on a longer time scale. The circuit has been fabricated in a 0.18 μm CMOS process and consumes only 1.1 nW-1.08 μW when tuned for operation from 20 Hz-20 kHz. It exhibits a dynamic range of 70 dB across typical speech frequencies.
Keywords :
CMOS integrated circuits; adaptive filters; audio signal processing; low-power electronics; signal detection; CMOS process; RMS estimation; adaptive-time-constant filter; frequency 20 Hz to 20 kHz; high-ripple peak detector; low-power audio-frequency magnitude detector; low-power magnitude detector; power 1.1 nW to 1.08 muW; size 0.18 mum; steady-state ripple; transient-rich signal analysis; Accuracy; Detectors; Equations; Mathematical model; Speech; Transconductance; Transistors; Analog processing circuits; CMOS integrated circuits; continuous-time circuits; envelope detectors; magnitude detectors; nonlinear dynamic circuits; peak detectors; ultra-low power;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2011.2179452