Circuit design techniques are described for switched-capacitor filters, modulators, rectifiers, detectors, and oscillators. The applications of these circuits in telecommunications, speech processing, and other signal-processing systems are also briefly discussed.

Switched-capacitor circuit design

Bandpass filters for communications applications are realized using an 80 MHz differential single-stage CMOS operational amplifier and a fully differential identical-resonator elliptic bandpass ladder filter configuration. Experimental results are given for a CMOS sixth-order 260 kHz elliptic bandpass filter with a Q-factor of 40, a clock frequency of 4 MHz, and a power dissipation of 70 mW.

High-frequency CMOS switched-capacitor filters for communications application

A single-chip speech spectrum analyzer which contains a 20-channel filter bank, a 9-bit-resolution analog-to-digital converter, and a 396-bit buffer memory is described. Several efficient design techniques were used to realize the equivalent 308th-order transfer functions on a single chip monolithic MOS circuit. A new time-division-multiplexed switched-capacitor filter technique is introduced which can easily cancel DC offsets which appear in the multiplexed channel outputs. The LSI was fabricated in 3.5-/spl mu/m CMOS technology, with a 7.0/spl times/6.5 mm/SUP 2/ die size, a power consumption of 150 mW, with a single power supply of +5 V. Experimental results show that designed performance was realized.

A single-chip 20-channel speech spectrum analyzer using a multiplexed switched-capacitor filter bank

The article provides a comprehensive overview of the history of how signal-processing researchers have been effectively transforming signal-processing algorithms into efficient implementations. Starting from the early days of analog circuits for signal processing, to digital signal processors (DSPs), to application specific DSPs and programmable DSPs, and to the trend of integrating a complete system on a single chip, this article provides a thorough coverage of the past and the present of design and implementation technology for signal processing systems. Moreover, it presents the exciting challenges faced by the study of the design and implementation of current and future signal processing applications. Topics covered include milestones in signal-processing integrated circuits, the past and future of the signal processor, signal processing in consumer applications, and design automation for signal processing.

VLSI design and implementation fuels the signal-processing revolution

A design strategy for micropower switched-capacitor filters is presented and illustrated with the design of a multipurpose second-order section. The filter, realized in a double-poly 6-/spl mu/m CMOS process, consumes 237 /spl mu/W if it is used as an equalizer (f/SUB c/=90 kHz, -V/SUB DD/=3 V) and only 72 /spl mu/W if it is used as a bandpass filter for 8 channels (f/SUB c/=192 kHz, V/SUB DD/=3 V). The dynamic range of the filter is over 60 dB and the total chip area is 3.5 mm/SUP 2/, including bonding pads.

A multipurpose micropower SC filter

A speech recognition monolithic audio spectrum analyzer, using NMOS switched capacitor filter technology, will be covered. Chip consists of 16 channels, each containing a bandpass filter, half-wave rectifier and low-pass filter to detect the frequency components of the voice signal.

http://ieeexplore.ieee.org/iel6/8297/25929/01156318.pdf

A monolithic audio spectrum analyzer for speech recognition systems

This paper will cover the development of two switched capacitor 20-pole filter chips meeting the frequency and phase response specifications for a full duplex 1200 baud modem fabricated in double-polysilicon NMOS.

Hsin-Fu Tseng

Papers

A monolithic audio spectrum analyzer for speech recognition systems

Monolithic filters for 1200 baud modems