Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Quantization Noise"”.
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Quantization noise in a digital signal processor for synthetic aperture radars.
Massachusetts Institute of Technology. Dept. of Electrical Engineering. Thesis. 1973. M.S.
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Low phase noise, high bandwidth frequency synthesis techniques
A quantization noise reduction technique is proposed that allows fractional-N frequency synthesizers to achieve high closed loop bandwidth and low output phase noise simultaneously. Quantization induced phase noise is the bottleneck in state-of-the-art synthesizer design, and results in a …
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A continuous-time multi-stage noise-shaping delta-sigma modulator for next generation wireless applications
… applications is investigated in this thesis. Quantization noise is suppressed aggressively by increasing the effective order of the noise transfer function (NTF). In order to increase the effective order of the NTF, a 2-loop sturdy multi-stage noise-shaping (SMASH) architecture is utilized. …
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Phase noise and spur reduction in an array of direct digital synthesizers
… purity. One method for producing tunable, low-noise source signals is to combine the outputs of multiple direct digital synthesizers (DDSs) arranged in a parallel configuration. In such an approach, if all noise is uncorrelated across channels, the noise will decrease relative to the combined …
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Sensitivity analysis of digital filter structures
… and its relationship to the filter output quantization noise power is derived. The sensitivity measure is simply the sum of the L₂ norm of all first order partials of the system function with respect to the system parameters; alternatively, the measure may be viewed as the output variance …
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Performance analysis of a multistage multicarrier demultiplexer/demodulator (M-MCDD) in the presence of interference and quantization error
… to being real-valued. This will also introduce quantization noise into the demultiplexed output. Due to the complexity induced by ACI and the combination of ACI with quantization noise, we rely on analytical techniques to arrive at approximate numerical solutions, with calculable error margins, …
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Analysis and Dynamic Range Enhancement of the Analog-to-Digital Interface in Multimode Radio Receivers
… and IS-95 spread spectrum systems to optimize quantization noise and distortion due to A/D overload. Lastly, methods for improving the dynamic range of the analog-to-digital interface such as nonuniform quantization, companding, and dither are presented. The development of a novel A/D using a …
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Tunable narrow bandpass Sigma-Delta analog-to-digital conversion for mobile communication terminals
… application. The ΣΔ ADC must be able to null the quantization noise at the frequency of the desired channel. The research considers the feasibility of varying this frequency for tuning different channels. This is a novel concept for ΣΔ systems and so the simplest form of ΣΔ structure was chosen …
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Digital Pulse Width Modulation: Analysis, Algorithms, and Applications
… the implementation of real applications, the noise shaping technique is employed to reduce the resolution of quantization without compromising the signal to quantization noise ratio.
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An implementation of an AMPS digital base station with adaptive Automatic Gain Control
… gain factors maximize the quantizer's Signal-to-Quantization Noise Ratio (SQNR) in a mean-square sense. Together, these techniques can be used to implement an adaptive Automatic Gain Control for cellular communications. Results from a comprehensive AMPS base station simulation will also be …
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Digital hologram recording systems: some performance improvements
… algorithms, understanding the in uence of noise and developing techniques to increase resolution and angular perspective range in reconstructions. The main original contributions of this research work presented in this thesis are: � A computer-interfaced automatic digital holographic …
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A square root analog to digital converter to optimally convert photonic signals for computed tomography
… is a Poisson process with an associated shot noise which rises with the square root of the number of photons received. An analog-to-digital converter (ADC) with a square root transfer function can quantize photonic signals with LSB size kept constant with respect to the photon shot noise. In …
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ΜΕΘΟΔΟΙ ΜΕΤΑΤΡΟΠΩΝ ΚΩΔΙΚΑ ΔΙΑΜΟΡΦΩΣΗΣ ΔΕΛΤΑ ΓΙΑ ΤΗ ΒΕΛΤΙΩΣΗ ΚΑΙ ΑΠΛΟΥΣΤΕΥΣΗ ΤΗΣΕΠΕΞΕΡΓΑΣΙΑΣ ΣΗΜΑΤΩΝ
… SEQUENCE OF THE HIGHER RATE, BUT OF NEGLIGIBLE QUANTIZATION NOISE DUE TO THE FILTER OPERATIONS. A SIMPLE DIGITAL NETWORK, A "RATE CONVERTOR", CAN RESTORE THE RATE OF THE FILTER OUTPUT SEQUENCE TO THAT OF THE INPUT SEQUENCE. WITH THE CODE CONVERSION METHOD, AN ADAPTIVE DM (ADM) SEQUENCE CAN BE …
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Compressive sensor networks : fundamental limits and algorithms
… in relation to fundamental operations such as quantization and parameter estimation. Since compressed sensing is originally formulated as a real-valued problem, quantization of the measurements is a very natural extension. Although several researchers have proposed modified reconstruction …
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Digital enhancement techniques for fractional-N frequency synthesizers
… ΔΣ fractional divider to achieve low in-band noise with a wide bandwidth is presented. The fractional divider employs a digital-to-time converter (DTC) to cancel out ΔΣ quantization noise in time domain, thus alleviating TDC dynamic range requirements. The proposed digital architecture adopts …
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A dot product kernel using rapidly switched analog circuit
… to a digital implementation for signal-to-quantization-noise ratios (SQNRs) of 30 dB to 24 dB, respectively. Simulations for the second design in a 28 nm FDSOI process show energy savings of 15.7x, 4x, 2.1x compared to a digital implementation running at the same sampling frequency for …
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Theory and applications of delta-sigma analogue-to-digital converters without negative feedback
… components that are precise and highly immune to noise and interference. In contrast, oversampling converters can achieve high resolutions (>20bits) and can be implemented using straightforward, high-tolerance analog components. In conventional oversampled modulators, negative feedback is applied …
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Machine learning applications in plant identification, wireless channel estimation, and gain estimation for multi-user software-defined radio
… value that will avoid clipping, while minimizing quantization noise. One of the methods uses an ANN to estimate the waveform’s peak and statistical moments. The other method uses an ANN to estimate the statistical distribution parameters that closely represent the voltage distribution of the …
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Low bit-rate speech encoding for digital mobile radio
… showed both coders to be reasonably robust to quantization noise. Both were graded quite good, with the Forward Adaptive performing slightly better, but with a slightly higher transmission bit rate for the same speech quality, than its Backward counterpart. The coders yielded acceptable speech …
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Ring oscillators for high performance clock synthesis and sensor interfaces
… on RO-based clock generation where the phase noise is degraded due to jitter accumulation. We present a synthesizer architecture that uses a low-noise passive multiphase generator which does not suffer from jitter accumulation and digital background calibration to correct for errors in the …
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