Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver

Design of Tunable Low-Noise Amplifier in 0.13um CMOS Technology for Multistandard RF Transceivers

The global market of mobile and wireless communications is witnessing explosive growth in size as well as radical changes. Third generation (3G) wireless systems have recently been deployed and some are still in the process. 3G wireless systems promise integration of voice and data communications with higher data rates and a superior quality of service compared to second generation systems. Unfortunately, more and more communication standards continue to be developed which ultimately requires specific RF/MW and baseband communication integrated circuits that are designed for functionality and compatibility with a specific type of network. Although communication devices such as cellular phones integrate different services such as voice, Bluetooth, GPS, and WLAN, each service requires its own dedicated radio transceiver which results in high power consumption and larger PCB area usage. With the rapid advances in silicon CMOS integrated circuit technology combined with extensive research, a global solutionswhich aims at introducing a global communication system that encompasses all communication standards appears to be emerging. State of the art CMOS technology not only has the capability of operation in the GHz range, but it also provides the advantage of low cost and high level of integration. These features propel CMOS technology as the ideal candidate for current trends, which currently aim to integrate more RF/MW circuits on the same chip. Armed with such technology ideas such as software radio look more attainable than they ever were in the past. Unfortunately, realizing true software radio for mobile applications still remains a tremendous challenge since it requires a high sampling rate and a wide-bandwidth Analog-to-Digital converter which is extremely power hungry and not suitable for battery operated mobile devices. Another approach to realize a flexible and reconfigurable RF/MW transceiver that could operate in a diverse mobile environment and provides a multiband and multistandard solution. The work presented in this thesis focuses on the design of an integrated and tunable low-noise amplifier as part of software defined radio (SDR)

Direct GMSK modulation at microwave frequencies

Congestion in the radio spectrum is forcing emerging high rate wireless communication systems into upper microwave and millimeterwave frequency bands, where transceiver hardware architectures are less mature. One way to realize a simple and elegant hardware solution for a microwave transmitter is to exploit the advantages of directly modulating the phase of the carrier signal. A modulation method requiring continuous phase control of the carrier signal over the full 360 degree range is Gaussian Minimum Shift Keying (GMSK). Unfortunately, it is very difficult to design a microwave circuit to provide linear phase control of a carrier signal over the full 360 degree range using traditional methods. A novel method of obtaining continuous, linear phase modulation of a microwave carrier signal over the full 360 degree range is proposed. This method is based on controlling a phase shifter, at a subharmonic of the desired output carrier frequency, and then using a frequency multiplier to obtain the desired output frequency. The phase shifter is designed to be highly linear over a fraction of the full 360 range. The frequency multiplier is a nonlinear circuit that shifts the frequency by *'N'. The subtle part of this nonlinear operation is that the multiplier also multiplies the instantaneous phase of the phase shifter output signal by *'N', thus expanding the linear phase shift range to the required 360 degrees. Using this nonlinear frequency multiplication principle, the modulator can readily be extended into the millimeterwave region. A prototype circuit is designed and performance results are presented for this method of carrier phase modulation at 18 GHz. The prototype circuit is realized with very simple hardware, containing only a single microwave active device. An extension to the modulator involving phase locking or injection locking of a power oscillator is also suggested for obtaining higher power modulated output signals. In addition to direct continuous phase modulation, the proposed method is also suitable for a wide variety of transceiver applications, including phase synchronization of antenna and oscillator arrays, phased array antenna beam steering, indirect frequency modulation, and ultra-small carrier frequency translation

Audio Mastering as a Musical Competency

In this dissertation, I demonstrate that audio mastering is a musical competency by elucidating the most significant, and clearly audible, facets of this competence. In fact, the mastering process impacts traditionally valued musical aspects of records, such as timbre and dynamics. By applying the emerging creative scholarship method used within the field of music production studies, this dissertation will aid scholars seeking to hear and understand audio mastering by elucidating its core practices as musical endeavours. And, in so doing, I hope to enable increased clarity and accuracy in future scholarly discussions on the topic of audio mastering, as well as the end product of the mastering process: records. Audio mastering produces a so-called master of a record, that is, a finished version of a record optimized for duplication and distribution via available formats (i.e, vinyl LP, audio cassette, compact disc, mp3, wav, and so on). This musical process plays a crucial role in determining how records finally sound, and it is not, as is so often inferred in research, the sole concern of a few technicians working in isolated rooms at a record label\u27s corporate headquarters. In fact, as Mark Cousins and Russ Hepworth-Sawyer (2013: 2) explain, nowadays “all musicians and engineers, to a lesser or greater extent, have to actively engage in the mastering process.” Thus, this dissertation clarifies the creative nature of audio mastering through an investigation of how mastering engineers hear records, and how they use technology to achieve the sonic goals they conceptualize

Ultra low power circuits for a miniature apnoea detection device

Imperial Users onl

Low harmonic distortion flash A/D converters incorporating dynamic element matching techniques

New dynamic element matching techniques are shown to reduce the harmonic distortion and improve the spurious-free dynamic range of flash ADCs. Resistor chain mismatch errors are negated by randomly rearranging the resistors each sample by utilizing 5(2{dollar}\sp{b}{dollar}-1) digital switches and b + 1 random control signals for a b-bit flash ADC. The integral and differential nonlinearity of a non-ideal flash ADC are derived for three common resistor chain mismatch errors; namely, geometric mismatches, linear gradient mismatches, and dynamic mismatches. The transfer function of a non-ideal flash ADC is also derived and the converter output is shown to consist of a scaled copy of the input, a DC gain, and conversion noise that is a function of the resistor mismatches. A comprehensive summary of dynamic element matching techniques given in literature is provided. In addition, the DEM network introduced by Galton and Jensen is shown to be equivalent to the generalized-cube network used in parallel processing architectures. An alternative version of this network that uses logic gates is also proposed

Design and Analysis of High Frequency Power Converters for Envelope Tracking Applications

In the field of power electronics, designers are constantly researching new methods to improve efficiency while optimizing dynamic performance. As communication technologies progress we are more often dealing with systems of increasing speed and complexity. For instance, from 1991 to 2013 we have observed the mobile broadband communication sector evolve from ~230 Kbits/s (2G) speeds to ~100 Mbits/s (4G LTE), a 430% increase in communication speed. In contrast, we have not observed the same evolutionary development in industrial power converters. Most switch-mode power supplies are still manufactured for 100 KHz to 800 KHz operating frequencies. The main reason for this is that most electrical devices only require steady-state DC power, so high speed conversion performance is largely unnecessary. But as size expectations for portable electronic devices continue to decrease, the only way to meet future demand is to realize power electronics that operate at much higher switching frequencies. Furthermore there is increasing demand to improve the transient response requirements in processor-based systems and achieve practical envelope tracking in RF communication systems. The most straightforward method of increasing the dynamic response for these systems is to increase the switching frequency of the power electronics in a sustainable and coherent manner