A micropower-compatible time-multiplexed SC speech spectrum analyzer design
Joseph Sylvester Chang, Yit Chow Tong · IEEE Journal of Solid-State Circuits · 1993
A micropower-compatible time-multiplexed switched-capacitor (SC) speech spectrum analyzer embodying several new design methodologies is described. In the bandpass filter (BPF) section, the DC offset differences between channels are reduced by a careful biquadratic filter design, and a capacitor sharing technique is employed to reduce chip area. A new time-multiplexed full-wave rectifier (FWR) is also proposed. Expressions for the errors that limit the accuracy of the running spectrum due to nonidealities are formulated. An experimental four-channel spectrum analyzer was fabricated and measurements from prototypes showed that the proposed design methodologies are satisfactory in achieving the design specifications.>