Adaptive Digital Signal Processing Algorithms Research Articles

Computationally efficient low-power sigma delta modulation-based image processing algorithm

Digital Image Processing has dominated Digital Signal Processing at the cost of more memory, resources, and high computational power. In image processing, filtering transformations and other operations need complex multiplications, and the multiplier is one of the most resources consuming elements. Recently, mitigating the multiplier complexity in the digital signal processing (DSP) algorithms sigma-delta modulation based general purpose and adaptive DSP algorithms are developed in MATLAB and compared with its counterpart multi-bit algorithms for functionality and area-performance-power in FPGA. The contemporary multiplier algorithms are also optimized to overcome the multiplier complexity challenge as computation becomes simple and fast. This paper extends the reported work by investigating the sigma-delta modulation approaches for developing a computationally efficient low-power image processing algorithm. The proposed model is designed, developed, and simulated in MATLAB. The simulation results are analyzed using SNR, MSE, and Peak SNR. The simulation results show that the proposed system can better mitigate the noise effect, making it robust for noisy environment.

A Digitally Assisted Nonlinearity Mitigation System for Tunable Channel Select Filters

This brief presents a low-complexity system for digitally assisting a channel select filter (CSF) to mitigate both even- and odd-order nonlinearities. The proposed solution is scalable and can be utilized for nonlinearity mitigation in different analog transceiver blocks. The system consists of an auxiliary path with a low-resolution analog to digital converter (ADC) enabling digital recreation and measurement of the distortion in the main path and relies on an adaptive digital signal processing algorithm to detect and tune the analog components to their optimal settings. The system provides robustness against process, voltage, and temperature variations, and the digital part requires an equivalent logic of only 42 k gates in CMOS technology, enabling cost-efficient implementation on integrated circuits. The operation of the system has been verified by using a tunable CSF capable of receiving a 10-MHz baseband signal interfaced to an external ADC. The results demonstrate that the proposed system is capable of tuning the CSF to its optimal bias voltage, providing a third-order intermodulation reduction of 14.5 dB.

Digital self-coherent detection

We review recent progresses on digital self-coherent detection of differential phase-shift keyed (DPSK) signal using orthogonal differential direct detection followed by high-speed analog-to-digital conversion and digital signal processing (DSP). Techniques such as data-aided multisymbol phase estimation for receiver sensitivity enhancement, unified detection scheme for multi-level DPSK signals, and optical field reconstruction are described. The availability of signal field information brings the possibility to compensate for some linear and nonlinear transmission impairments through further DSP. An adaptive DSP algorithm for simultaneous electronic polarization de-multiplexing and polarization-mode dispersion compensation is also presented.

Experimental verification of preset time count rate meters based on adaptive digital signal processing algorithms

Experimental verifications of two optimized adaptive digital signal processing algorithms implemented in two pre set time count rate meters were per formed ac cording to appropriate standards. The random pulse generator realized using a personal computer, was used as an artificial radiation source for preliminary system tests and performance evaluations of the pro posed algorithms. Then measurement results for background radiation levels were obtained. Finally, measurements with a natural radiation source radioisotope 90Sr-90Y, were carried out. Measurement results, con ducted without and with radio isotopes for the specified errors of 10% and 5% showed to agree well with theoretical predictions.

Novel adaptive digital signal processing algorithm for a stationary reticle seeker

Conventional stationary reticle seeker uses an analog signal processing technology to extract a target position in the field of view. The analog technology is optimized for only frequency modulation signals, which makes it difficult to use various and adaptive signal processing, and causes the performance limit of the conventional technology. We propose a novel adaptive digital signal processing algorithm to overcome the performance limit. The proposed algorithm classifies the modulation signals into the FM and FM/AM signals and applies a different signal processing algorithm, which is optimized for the modulation characteristics of each signal. The algorithm also employs an adaptive clipping level to minimize the noise effect. Our simulation results show that the proposed algorithm is superior to the conventional one in terms of the linearity of the static gain curve, tracking performance, and robustness against noise.