Gaussian-shaped Optical Frequency Comb Generation for Microwave Photonic Filtering

Using only electro-optic modulators, we generate a 41-line 10-GHz Gaussian-shaped optical frequency comb. We use this comb to demonstrate apodized microwave photonic filters with greater than 43-dB sidelobe suppression without the need for a pulse shaper.Comment: 3 pages, 4 figure

Hybrid methods for function generation

A method of function generation is discussed based on the use of hybrid digital analogue techniques. A brief description of a quantizer is given together with some experimental results. The purpose of this unit is to give the derivative with respect to time (in quantized form) of a variable. Units of this type used in conjunction with pulse modulators, which are also described, are shown to be capable of performing a wide variety of analytic functions. The application to correlation functions, using magnetic core storage for time delays, is also discussed. Another application is a fast analogue/digital converter with an incremental bit resolution time of one micro-second. The possibility of extending the application to generation of arbitrary functions of one or more variable is considered and one possible form of instrumentation, based on the use of magnetic core storage, is described

Adaptive design of delta sigma modulators

In this thesis, a genetic algorithm based on differential evolution (DE) is used to generate delta sigma modulator (DSM) noise transfer functions (NTFs). These NTFs outperform those generated by an iterative approach described by Schreier and implemented in the delsig Matlab toolbox. Several lowpass and bandpass DSMs, as well as DSM\u27s designed specifically for and very low intermediate frequency (VLIF) receivers are designed using the algorithm developed in this thesis and compared to designs made using the delsig toolbox. The NTFs designed using the DE algorithm always have a higher dynamic range and signal to noise ratio than those designed using the delsig toolbox

Output Filter Aware Optimization of the Noise Shaping Properties of {\Delta}{\Sigma} Modulators via Semi-Definite Programming

The Noise Transfer Function (NTF) of {\Delta}{\Sigma} modulators is typically designed after the features of the input signal. We suggest that in many applications, and notably those involving D/D and D/A conversion or actuation, the NTF should instead be shaped after the properties of the output/reconstruction filter. To this aim, we propose a framework for optimal design based on the Kalman-Yakubovich-Popov (KYP) lemma and semi-definite programming. Some examples illustrate how in practical cases the proposed strategy can outperform more standard approaches.Comment: 14 pages, 18 figures, journal. Code accompanying the paper is available at http://pydsm.googlecode.co