With an increasing number of transistors integrated on a single die, the need for global on-chip interconnectivity is growing. Long interconnects, in turn, have very large capacitances which consume a large share of a chip’s total power budget. Power consumption can be lowered in several ways, mainly by reduction of switching activity, reduction of total capacitance and by using low voltage swing. In this project, the issue is addressed by proposing a new encoding based on Pulse Width Modulation (PWM). The implementation of this encoding will both lower the switching activity and decrease the capacitance between nearby wires. Hence, the total effective capacitance will be reduced considerably. Schematic level implementation of a robust transmitter and receiver circuit was carried out in CMOS090, designed for speeds up to 100 MHz. On a 10 mm wire, this implementation would give a 40% decrease in power dissipation compared to a parallel bus having the same metal footprint. The proposed encoding can be efficiently applied for global interconnects in sub-micron systems-on-chip (SoC).

Class D amplifiers are becoming increasingly popular in audio devices. The strongest reason is the high efficiency which makes it advantageous for portable battery-driven products. Infineon Technologies is developing products in this area, and has recently filed a patent application regarding an implementation of a part of the class D amplifier. The aim of this Master’s thesis is to evaluate a digital open-loop implementation of a class D amplifier, using the pending patent solution, and discuss the differences from an analog closed-loop implementation. The focus has been on generating a high resolution PWM signal with a relatively low clock frequency. To achieve this, a hybrid of a counter and a self-calibrating tapped delay-line are used as a pulse generator. A model of the pulse generator was developed which made it possible to study how sampling frequency and different types of quantization affected quality parameters such as THD and SNR. With the results from the model two systems were implemented and simulated in HDL and as circuit schematics. The proposed digital open-loop class D amplifier was found to be useful in voice-band applications and for music. Since the open-loop structure suffers from poor rejection of power supply ripple, either error correction or a regulated power supply is needed. If much effort is put on the different parts of the amplifier the result can be really good but, depending on other constraints on the system, it may be simpler and less time consuming to use the analog circuit with feedback to achieve hi-fi quality. In summary, the combination of a counter and a self-calibrating tapped delay-line as a pulse generator is very useful in high resolution low-power systems. To avoid errors the delay-line and calibration can be made very accurate but with the expense of higher power consumption and area. However, the technique benefits from the small and fast logic devices available in deep sub-micron process technologies, which may finally lead to an advantage in power consumption and cost over the closed-loop analog solution.

Small size of electronic product with high layout density is the future trend in today¡¦s high speed digital circuit design. A circuit designer is obliged to optimize the best solution of circuit layout in a limited area in order to both keep a good signal integrity¡]SI¡^, and save the layout space. Meander delay line is one of the challenging topic in high-speed circuit. In this dissertation, a effective method is provided to design a meander delay line, and FDTD and HFSS are matched up to predict the behavior and the character of the meander delay line; the differential meander delay line is compared with the single meander delay line, and the behavior and phenomena of the differential meander delay line are discussed. To reduce couple power, the differential meander line of design would be a new thinking. The most important point in this thesis, the complete flows of designing single meander lines and differential meander lines are provided, and designer could follow the steps of the proposed method to design a perfect and practical meander line with both keeping good SI and using least layout space. The effect of the design parameters of the meander line on the signal quality both in time-domain and frequency-domain is theoretically and experimentally investigated. FDTD method and the commercial tool HFSS are employed for the numerical study in this work.

Theory, design, fabrication and characterization of on-chip optical beam steering systems are presented in this dissertation. Silicon photonics is being considered for integration with conventional CMOS technology for large-band width and low loss on and off-chip communications. We choose silicon nanomembrane, or silicon-on-insulator (SOI) substrates for implementation of large-angle and agile beam steeres. While working on the targeted device, we contributed to the theory, modeling, engineering and implementation of different building blocks. Multimode-interference couplers (MMIs) constitute important parts of this dissertation. These devices are commonly used as on-chip beam splitters, optical switches and on-chip static phase shifters. The MMIs’ principles of operation are suited in more details and design rules are derived for the first time. MMI based beam splitters with number of outputs as large as 12 are fabricated and tested on SOI wafers. Traditionally, MMIs devices were designed by means of computationally expensive numerical simulations. Numerically and experimentally, we show that our analytical design rules make design of MMIs with low insertion loss and highly uniform outputs possible without additional optimization processes. Optical phased arrays include phase shifter blocks. In the first prototype, we use micro-heaters for tuning the optical phase. The bread-loafing effect, which is generally considered an undeniable phenomenon in the silicon industry, is engineered to realize a mechanical structure to efficiently direct heat toward the silicon waveguides. We also investigate slow light photonic crystal based delay lines to be used as phase shifters. An important drawback of such devices is the low coupling efficiency between slow-light photonic crystal waveguides and fast light strip waveguides. We numerically and experimentally investigate the coupling efficiency, and show for the first time that a few-period long fast-light photonic crystal waveguide without any group index tapering suffices for efficient coupling. The prototype is fabricated, packaged and tested and optical beam steering angle over ±30degrees is demonstrated. Finally, preliminary investigations for 3D implementation of the beam steerer system are presented to clarify the approaches to take for future works. / text

In this thesis, principles of a pulse modulated frequency modulated continuous wave radar is analyzed and adding time delay to transmitted signal in the laboratory environment performed. The transmitted signal from the radar has a time delay for traveling the distance between radar and target. The distance from radar to target is more than one kilometers thus test of the functionality of the radar in the laboratory environment is unavailable. The delay is simulated regarding to elapsed time for the transmitted signal to be received. This delay achieved by using surface acoustic wave (SAW) delay line in the laboratory environment. The analyses of the components of the radar and the delay line test board are conducted.

The development of communications technologies has led to an ever-increasing requirement for a wider bandwidth of microwave signal processing systems. To overcome the inherent electronic speed limitations, photonic techniques have been developed for the processing of ultra-broadband microwave signals. A dispersive delay line (DDL) is able to introduce different time delays to different spectral components, which are used to implement signal processing functions, such as time reversal, time delay, dispersion compensation, Fourier transformation and pulse compression. An electrical DDL is usually implemented based on a surface acoustic wave (SAW) device or a synthesized C-sections microwave transmission line, with a bandwidth limited to a few GHz. However, an optical DDL can have a much wider bandwidth up to several THz. Hence, an optical DDL can be used for the processing of an ultra-broadband microwave signal. In this thesis, we will focus on using a DDL based on a linearly chirped fiber Bragg grating (LCFBG) for the processing of broadband microwave signals. Several signal processing functions are investigated in this thesis. 1) A broadband and precise microwave time reversal system using an LCFBG-based DDL is investigated. By working in conjunction with a polarization beam splitter, a wideband microwave waveform modulated on an optical pulse can be temporally reversed after the optical pulse is reflected by the LCFBG for three times thanks to the opposite dispersion coefficient of the LCFBG when the optical pulse is reflected from the opposite ends. A theoretical bandwidth as large as 273 GHz can be achieved for the time reversal. 2) Based on the microwave time reversal using an LCFBG-based DDL, a microwave photonic matched filter is implemented for simultaneously generating and compressing an arbitrary microwave waveform. A temporal convolution system for the calculation of real time convolution of two wideband microwave signals is demonstrated for the first time. 3) The dispersion of an LCFBG is determined by its physical length. To have a large dispersion coefficient while maintaining a short physical length, we can use an optical recirculating loop incorporating an LCFBG. By allowing a microwave waveform to travel in the recirculating loop multiple times, the microwave waveform will be dispersed by the LCFBG multiple times, and the equivalent dispersion will be multiple times as large as that of a single LCFBG. Based on this concept, a time-stretch microwave sampling system with a record stretching factor of 32 is developed. Thanks to the ultra-large dispersion, the system can be used for single-shot sampling of a signal with a bandwidth up to a THz. The study in using the recirculating loop for the stretching of a microwave waveform with a large stretching factor is also performed. 4) Based on the dispersive loop with an extremely large dispersion, a photonic microwave arbitrary waveform generation system is demonstrated with an increased the time-bandwidth product (TBWP). The dispersive loop is also used to achieve tunable time delays by controlling the number of round trips for the implementation of a photonic true time delay beamforming system.

This diploma thesis deals with pitch shifting methods of acoustical signals. The theoretic part of this thesis involves description of three different pitch shifting techniques, these are the method using a modulated delay line, PICOLA method and method using a phase vocoder. The first two methods represent the processing in time domain, the third method represents the processing in frequency domain. In relation with the PICOLA method, the thesis also mentions algorithms for pitch estimation. The practical part demonstrates the use of these methods. There is described a sampler virtual musical instrument based on the playback of the sounds stored in memory. In this part the particular units providing the required functionality are described. The generating of sounds is controlled by the MIDI protocol. In the sampler is implemented the PICOLA method.

Breaking Rayleigh’s "curse" and resolving infinitely small spatial separations is one motivation for developing super-resolution in imaging systems. It has been shown that an arbitrarily small distance between two incoherent point sources can be resolved through the use of a spatial mode sorter, by treating it as a parameter estimation problem. However, when extending this method to general objects with many point sources, the added complexity of multi-parameter estimation problems makes resolution of general objects quite challenging. In the first part of this thesis, we propose a new approach to deal with this problem by generalizing the Richardson-Lucy (RL) deconvolution algorithm to accept the outputs from a mode sorter. We simulate the application of this algorithm to an incoherent confocal microscope using a Zernike spatial mode sorter rather than the conventional pinhole. Our method can resolve general scenes with arbitrary geometry. For such spatially incoherent objects, we find that the resolution enhancement of the sorter-based microscopy using the generalized RL algorithm is over 30% higher than the conventional confocal approach using the standard RL algorithm. This method is quite simple and potentially can be used for various applications including fluorescence microscopy. It could also be combined with other super-resolution techniques for enhanced results. The second part of this thesis explores the potential for the Herriott cell to be used as an image-preserving delay line. In quantum imaging, entangled photons are often utilized to take advantage of their spatial and temporal correlations. One photon (“the signal”) interacts with the system to be measured and the other (“the herald”) is used to trigger the detection of the signal. However, for a typical high-sensitivity camera, there is a delay on the order of 20 ns between the trigger and the sensor becoming active allowing for the signal to be recorded. An image-preserving delay line (IPDL) serves to store a photon without distorting the spatial structure and losing the spatial and temporal correlations. It is commonly made with a series of 4f systems to repeatedly image the light field. We propose to use the Herriott cell as an image-preserving delay line. We tested 10 of the lower-order HG modes and found it was able to preserve almost all of them with high fidelities (>90%), with the only exceptions being the largest modes (HG03 and HG30) at the longest delay (7.9 m) where the fidelity was still >86%. In addition to these modes, it was also able to store general images. This application of the Herriott cell affords insights into miniaturizing IPDLs, which tend to occupy a significant amount of space. Overall, these two projects offer novel insight and application to the world of quantum imaging.

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