The resolution of analog-to-digital converters can be distinguished as absolute resolution, or average resolution. This study reviews average resolution enhancement techniques and proposes a method which is particularly applicable as a low-cost modification to a high-speed waveform acquisition system. This method uses oversampling combined with computationally simple digital filtering to...
This thesis describes the development of a flash analog-to-digital converter based on
current-mode technique. The advantages of current -mode technique are higher speed,
smaller chip area, and simple division of reference current based on current mirror. A
current-mode comparator is designed consisting of a cascode current mirror and a
current...
Delta-Sigma Modulator-based Analog-to-Digital converter design is an active area of research. New topologies require extensive simulations to verify their performance. A series of improvements were made to an existing circuit simulation package in order to speed the simulation process for the designer. Various examples of these improvements are presented in...
Oversampling analog-to-digital and digital-to-analog converters are gaining more
popularity in many signal processing applications. Delta-sigma modulators are used in practical applications of oversampling systems because of their apparent practical advantage over other oversampling converters in terms of insensitivity to the inevitable imperfection of the analog circuitry.
In Δ∑ modulators, analog...
This thesis presents the design of a 10 bit Analog to
Digital Converter which consists of a 6 bit flash followed
by a 4 bit pipeline architecture. The total system is
described and the 4 bit pipeline is implemented on a bipolar
process.
The objective of this research is to...
Oversampled delta-sigma modulation is one of the widely used A/D conversion
techniques for narrow bandwidth signals. In this study several new lowpass and
bandpass delta-sigma modulator architectures as well as novel pseudo-N-path integrators
that can be used in implementing these architectures are proposed.
By using multiplexing techniques the new lowpass...
Multi-level decision feedback equalization (MDFE) is an effective sampled signal processing technique to remove inter-symbol interference (ISI) from disk read-back signals. Parallelism which doubles the symbol rate can be realized by utilizing the characteristic of channel response and decision feedback equalization algorithm.
A mixed-signal IC implementation has been chosen for...
Multi-level decision feedback equalization (MDFE) is a sampled signal processing technique for data recovery from magnetic recording channels which use the 2/3(1,7) run length limited code. The key adaptive feedback loops in MDFE are those which perform the timing recovery, gain recovery, dc offset detection, and adaptive equalization of the...
Delta-sigma modulators are currently a very popular technique for making high-resolution
analog-to-digital and digital-to-analog converters (ADCs and DACs). Most
delta-sigma modulators in production today employ single-bit quantization because a 1-bit DAC is inherently linear, whereas a multi-bit DAC is not. Were it not for this drawback,
the use of multi-bit...
This thesis describes compensation techniques for cascaded delta-sigma A/D
converters (ADCs) and high-performance switched-capacitor (SC) circuits. Various
correlated-double-sampling (CDS) techniques are presented to reduce the effects of the
nonidealities, such as clock feedthrough, charge injection, opamp input-referred noise and
offset, and finite opamp gain, in SC circuits. A CDS technique...
The precise measurement of a capacitance difference or ratio in a digital form is
very important for capacitive sensors, for CMOS process characterization as well as for the
realization of precise switched-capacitor data converters, amplifiers and other circuits
utilizing ratioed capacitors. This thesis introduces design techniques for on-chip capacitor
ratio...
Continuous process scale-down and emerging markets for low-power/low-voltage mobile systems call for low-voltage analog integrated circuits. Switched-capacitor (SC) circuits are the building blocks for analog signal processing and will encounter severe overdrive problems when operating at low voltage conditions. There exist three techniques to solve the problem, but with their...
Pipeline analog-to-digital converters (ADCs) have long been used in high-speed systems for power-efficient data conversion. Broadband communication and video processing systems are placing high demands on converter accuracy and speed (above 14 bits and in the multiple-MHz range). The increasing converter requirements coupled with lower supply voltages in modern processes...
A new approach to oversampled delta-sigma A/D converters ( AZ modulators ) is introduced, where a differential pseudo-Npath filter stage is used as a basic cell. In this band-pass application, the z to -zN transformation is employed to realize a RAM-type pseudo-2-path lossless integrator. The bandpass second-order and 4th-order delta-sigma...