Higher data rate hard disk drives(HDD) and improved read channel electronics are demanding preamplifier performance be extended well beyond 1 Gb/s. Historically, preamplifier power requirements were of low priority; however, with increased demand for battery powered devices such as laptops, MP3 players, personal video recorders, andmanyother wireless hand-held devices, power consumption has become an important design parameter.Furthermore, in order to continue to increase drive capacities, new read-write head technologies(vertical recording and TGMR heads) are demanding innovative preamplifier circuitsolutions.Today's production preamplifiers possess a wide band response of 2.5 MHz-600 MHz; however next generation preamplifiers willrequire response greater than 250 KHz-1 GHz.Low corner frequencies below 250 KHz present read recovery (sleep-to-read, write-to-read, etc) challenges which can limit drive capacity. This project targets a > 2 Gb/s TGMR (tunneling giantmagneto-resistive) read path for verticalrecording HDDs. A high performance BiCMOS process (IBM's 0.5?m 5HP process)is essential due to the large transconductances, low noise and highspeed requirements of the read path's first stage. System frequency limitations at the input are a result of the large TGMR read sensor and preamplifier input capacitance. Due to read head and preamplifier manufacturingvariations, resistive feedbackaroundthe firststage is usedto seta controlled input impedance targeted to match the interconnect transmission line. Head resistance variations lead to gain variations; however, the TGMR element becomes more sensitive with larger resistance. This, to a first order approximation, acts like an automatic gain control and reduces variations in gain due to the head.

In order to prepare for the prospective need for heritage 3D recording, the main objective of this research was to investigate a new depth measuring method that can reduce identified limitations of current point-to-point measuring approaches. The limitations were time-money consumption, intrusiveness, accuracy assumption and efficiency. In many disciplines other than heritage recording, optical moir?? interferometry techniques (OMIT) are well developed as a measuring method and are considered fast, non-intrusive, accurate, and efficient. Based on these considerations, this research hypothesized that OMIT, as a measuring method, is feasible with respect to time-consumption and accuracy in acquiring depth measurement for fine-grain surface relief for historic recording. To test this hypothesis, a feasibility investigation was carried in which OMIT was used for surface relief topographic recording. This goal was approached by performing a comparison study between the OMIT measuring method as the investigated method and the hand measuring method as the control method. For each method, the comparison required performing eight experimental samplings of relief recording for a pre-designed physical model surface. The data collected from the hand measuring samples were the depth measurements of predefined points on the model surface and the timeconsumption for both measuring and data preparing processes. The data collected from the OMIT measuring samples were moir?? dark fringes generated on the model surface and the time-consumption for both moir?? generating and data preparing processes. For measurement accuracy evaluation, the collected depth data were prepared in the form of topographic contour drawings. For the OMIT feasibility evaluation, a comparison was carried out to examine the resulting topographic contour drawings for depth measurement accuracy level and measuring process time-consumption. In conclusion, the OMIT method showed higher depth measurement accuracy levels and lower process time-consumption than the hand method. The OMIT method also demonstrated less intrusiveness and more efficiency. This superiority validates the feasibility of using fine-grain surface relief for heritage recording purposes. Finally, the observed advantages of the OMIT method were presented to establish potentials for future developments and investigations. The observed limitations of the method were also pointed out to establish trends for recommendations and further studies.

Thesis (M.A.)--University of Wisconsin--Milwaukee, 1998. / Online version produced by the University of Wisconsin-Madison Libraries. Title from title screen (viewed Nov. 8, 2001). Includes bibliographical references (leaves 178-183). Online version of the print edition.

In mid- to late-1960s America and Britain, against the backdrop of escalating socio-political disappointment, countercultural ideologies and fantasies of a musical youth dovetailed with improvements in recording technologies to generate new sonic languages of limning in sound utopian pastoral spaces to which recordists and listeners could escape, virtually. Seeking alternative spaces that their alternative identities could more comfortably inhabit became a central project of many progressive groups and individuals, often, but not always, hailing from middle-class white society. The cultural and musical trends did eventually have a global sway. Coeval advances in sound recording and reproduction technologies made musical recordings a major avenue through which the sought spaces were limned and even materialized sonically, but other media, especially album cover art and film in conjunction with musical soundtracks, provided additional avenues for pastoral spatial projects of this generation and afford us ancillary resources for better understanding these projects. While the specific utopian spatial projects and the underlying ideologies of musicians working in various branches of country rock, soft rock, progressive country, progressive bluegrass, art rock, Afrocentric avant-garde jazz, and proto-New Age music were not always exactly the same, there were considerable overlaps in the societal sources of their disaffections, the wellsprings of their inspiration, and in the textural sonic languages they developed in the recording studio. Unlike music with overtly spatial projects, the sonic aspects of music that subtly captures a hyper-real sense of the natural have remained underconsidered and their contribution to the aesthetic and psychological impact of music has slipped by under the radar of most listeners' conscious attention. This dissertation, then, is an attempt to analyze the subtle acoustic and musical communicative codes devised by musicians and recordists that do inform later music. Through close listening and textual analysis, this dissertation identifies the different levels at which spatial allusions are encoded into a musical product. Ethnographic interviews help distinguish between deliberate manipulations of studio technology and responses based in tacit understandings thereof. An overall cross disciplinary approach, borrowing especially from acoustics and psychoacoustics, aided me substantially with the analyses. / text

A multi-channel wireless implantable neural recording (WINeR) system for electrophysiology and behavioral neuroscience research applications was proposed. The system is composed of two units: a system-on-a-chip (SoC) transmitter (Tx) unit and a receiver (Rx) unit. In the Tx unit, the outputs are combined with marker signals and modulated into pulse widths after the neural signals are amplified and filtered by an array of low-noise amplifiers (LNA). The next step involves time-division multiplexing (TDM) of pulse-width modulation (PWM) signals. The TDM-PWM signal drives RF transmitter block and is transmitted by an antenna. To satisfy the needs of neuroscientists during animal experiments, the proposed WINeR system provides long-term recording with inductive powering and stimulus-artifact rejection for closed-loop operations, which requires simultaneous stimulation and recording. The Rx is another critical unit for wireless-link communication. To increase the area of wireless coverage, multiple antennas are used for the Rx. In addition, the automatic frequency-tracking method is used to track free-running Tx frequencies, and a smart time-to-digital conversion method is used to reduce noise and interference. A high-throughput computer interface and software are also developed to continuously receive and store neural data. The WINeR system is a potential tool for neuroscientists due to several advantages, such as a reliable wireless link with large coverage and no blind spots, low power consumption, an unlimited power source, and a stimulation function.

An assessment is made of the impact of a thermally bloomed atmosphere on target image quality. The steady-state phase perturbations due to blooming and the effects of the distortion on return wave-fronts are determined using a physical optics propagation code. The wavelength of the return radiation used to sense the distortions is shown to be an important consideration in the stability of the return image. The return targets images for several realistic scenarios are reconstructed based on the incoherent point spread function for each isoplanatic region of the object (target) plane. Special requirements of the back propagation algorithm are discussed with respect to "point source" geometry, tilt, tilt sensitivity, and isoplanatism criterion. The wave optics approach is shown to agree with the experimental results in regards to image blur and distortion. The stability of the reconstructed images is discussed using merit functions defining the amount of blur, distortion, and degradation in peak irradiance. The merit functions are shown to correlate well with the scenario distortion number used to define the degree of blooming induced in the forward propagation.

No description available.

No description available.

The following thesis is an examination of audio engineering for television broadcast production. The extensive sound design, implementation, and production of television programming are to be examined from the perspective of four individual productions of diverse genres. A variety of skills necessary to produce each of the programs are discussed in detail.

No description available.