Solid state devices are used more and more to provide computerised control and sensing in high temperature environments. The market for electronics, in instrumentation and control systems in down-hole applications for petroleum exploration, requires increased performance from electronic components in terms of both duration and temperature. Substantial improvements in performance and cost of com...

A second order switched capacitor sigma-delta modulator operating at a supply voltage of 1 V is presented. This low supply voltage restricts the gate overdrive voltage available for switching transistors. The design relies on the elimination of critical switches by using a modified switched op amp for the integrator and novel switched half-supply and reference voltage generators. The design has...

ACKNOWLEDGMENT This thesis acknowledges the following people for their support and assistance: First, I would like to thank my advisor, Professor Un-Ku Moon, for allowing me to be part of his research group, and for supporting me financially. I learned alot from his wide knowledge of circuits. I also would like to thank my co-advisor, Professor Gábor C. Temes, for his assistance, and for his jo...

In wide band communication systems, low power and high speed ADCs forms the main building blocks. These ADCs are commonly seen in the front end of the radio frequency receivers. Comparators are used in these ADCs. A CMOS Comparator design, based on amplifier-push pull inverter circuit is elaborated in this paper, which is intended to be used as the 1-bit ADC required for the implementation of a...

An eighth-order switched-current bandpass delta-sigma modulator is described. Simulations indicate that our 1.2pm CMOS implementation will achieve a S N R of 90dB in the band 10 MHzk150 KHz when clocked at 40 MHz. The modulator makes use of a switched-current resonator based on the N-path technique and the resonator employs regulated-cascode current-copiers to simultaneously achieve high speed ...

Digital radio receivers must perform the analog-to-digital conversion of bandpass signals. For signals with small relative bandwidths, bandpass XA analog-to-digi ta l converters offer high signal-to-noise ratios at significantly lower sampling rates than are required for lowpass ZA converters, while still providing excellent linearity. A 4thorder bandpass ZA modulator implemented in a 3 pm CMOS...

A new noise-shaping coding scheme is derived by using an autoregressive moving average model and by bounding and minimizing its reconstruction error. The stability of the system and performance can be analysed easily. All-zero first order and second order shaping filters are used to study the effect of the proposed scheme on the perceptual quality of speech signals.

An architecture to simplify the circuit implementation of analog-to-digital (A/D) converter in a sigma-delta (ΣΔ) modulator is proposed. The two-step quantization technique is utilized to design architecture of ΣΔ modulator. The architecture is based on dividing the A/D conversion into two time steps for achieving resolution improvement without decreasing speed. The novel architecture is design...

In this paper we propose a framework for stability analysis of EA modulators, and argue that limit cycles for constant inputs are natural objects to investigate in this context. We present a number of analytical and approximate techniques to aid the stability analysis of the double loop and interpolative modulators, and use these techniques to propose ways of improved design that explicitly tak...