A method of fabricating a semiconductor structure including the steps of providing a silicon substrate (10) having a surface (12), forming on the surface (12) of the silicon substrate (10), by atomic layer deposition (ALD), a seed layer (20;20') characterised by a silicate material and forming, by atomic layer deposition (ALD) one or more layers of a high dielectric constant oxide (40) on the seed layer (20;20').

Method for fabricating a semiconductor structure including a metal oxide interface with silicon

A multi-channel digital transceiver (400) receives uplink radio frequency signals and converts these signals to digital intermediate frequency signals. Digital signal processing, including a digital converter module (426), is employed to select digital intermediate frequency signals received at a plurality of antennas (412) and to convert these signals to baseband signals. The baseband signals are processed to recover a communication channel therefrom. Downlink baseband signals are also processed and digital signal processing within the digital converter module (426) up converters and modulates the downlink baseband signals to digital intermediate frequency signals. The digital intermediate frequency signals are converted to analog radio frequency signals, amplified and radiated from transmit antennas (420).

Multi-channel digital transceiver and method

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

In this paper, various technological and topological considerations for the design of monolithic MOS switched-capacitor (SC) filtering systems are described. The properties of the passive and active devices typically available in depletion-load NMOS and CMOS technologies are presented as they relate to various SC peformance parameters. Layout techniques for improving specific performance parameters are also given. An overview of MOS operational-amplifier design emphasizes technological considerations in the design of high-performance SC systems. Finally, several important techniques are reviewed for maximizing dynamic range in SC circuits.

Technological design considerations for monolithic MOS switched-capacitor filtering systems

High-resolution oversampling analog-to-digital-to-analog converters are proposed. The converters utilize multistage noise shaping modulation techniques that can be implemented with VLSI MOS technology. The modulators consist of multiconnected single-integration delta-sigma modulation loops. Quantization noise in the first delta-sigma loop is requantized by the next delta-sigma loop and cancelled by adding the requantized noise to the first-stage signal. Quantization noise in the modulated signal is suppressed by double or multiple integration gain. Modulator resolution increases with the number of stages without feedback loop instability problems. A three-stage multistage noise shaping modulator with 1-bit quantization achieves the equivalent of 16-bit resolution for the hi-fi audio band at 2-MHz sampling rate. Simulation results show that analog-to-digital and digital-to-analog converter circuits constructed of switched capacitors do not require highly accurate components. >

Oversampling A-to-D and D-to-A converters with multistage noise shaping modulators

The number of current sources and switches necessary for a plurality of unit D/A converters using equal reference currents, are drastically reduced to reduce the parasitic capacitance coupled to current output lines, by converting a plurality of digital signals of a predetermined bit, which are divided from an input digital signal, into an analog current unit D/A converters and by converting the analog current in a manner to correspond to the weights of the corresponding input digital signals, thereby to synthesize the currents The fixed reference digital signal is inputted to the D/A converter for cancelling offsets The offsets of a plurality of analog output signals in positive and opposite phases obtained by branching the output of the D/A converter are individually detected After this, the DC offset values of the individual analog outputs are used as offset adjusted negative feedback signals for a desired value One of them is the digital signal to be fed back to the input portion of the D/A converter whereas the other is the analog signal to be fed to a path portion obtained by branching the output of the D/A converter

Converter, offset adjustor, and portable communication terminal unit

A method of controlling the time constant of a filter for use in a radio receiver which receives a signal, transmitted from a transmitting station at a predetermined period, intermittently at the predetermined period and demodulates and delivers the received signal, a filter circuit having the time constant control function based on the method, and a radio receiver having the filter circuit. Preferably, the filter has its time constant switchable stepwise and specifically, parallel connection of capacitors or shortcircuiting of resistors is controlled by turning on/off switches. A controller within the filter circuit or the radio receiver performs control for applying a predetermined periodical signal (or standard pulse signal) to the filter and controlling the time constant of the filter in accordance with an output signal (or triangular pulse) during a first time zone within each operation interval for the intermittent reception and for filtering the signal from the transmitting station and causing a demodulating circuit to demodulate and deliver a filtered signal.

Method of controlling filter time constant and filter circuit having the time constant control function based on the method

A second generation LSI codec has been implemented. In this chip, switched-capacitor filters, a charge redistribution encoder and decoder, voltage references, a signaling logic circuit, and all necessary functions for voice-PCM conversion are integrated. The authors describe the codec and summarizes its characteristics.

A single-chip CMOS filter/codec

An over-sampling analog-to-digital converter using a current switching circuit 102 as a local digital-to-analog converter, wherein a difference between the output currents Isig and Iq of a voltage-to-current converter circuit 101 and a current switching circuit is integrated by a capacitor 105 of which the one end is grounded to a dc potential VB. Further, the current switching circuit 102 has many bits to decrease the difference current between the signal current Isig and the feedback current signal Iq. Moreover, the level-shifting function of the voltage-to-current converter circuit 101 makes it possible to apparently subtract the dc component from the input analog signal Vsig which is produced based on an internally generated dc voltage as a dc bias voltage, and to decrease a change in the voltage between the electrodes of a capacitor caused by the integration of current.

Over-sampling analog-to-digital converter using a current switching circuit as a local digital-to-analog converter

Disclosed is an interpolative A/D converter for converting an over-sampled analog signal into a digital signal without the occurrence of over slope distortions, wherein the difference between the analog input signal and an analog feedback signal derived from the converter output through D/A conversion is integrated, the integrated output is compared with several reference voltages and, after being converted into a digital signal, the comparison result is integrated in a digital manner to complete a digital output signal of the A/D converter.

Kazuo Yamakido

Papers

Converter, offset adjustor, and portable communication terminal unit

Method of controlling filter time constant and filter circuit having the time constant control function based on the method

A single-chip CMOS filter/codec

Over-sampling analog-to-digital converter using a current switching circuit as a local digital-to-analog converter

Linear interpolative analog-to-digital converter