Design and FPGA Implementation of Variable FIR Filters using the Spectral Parameter Approximation and Time-Domain Approach

This brief present a design and FPGA implementation of variable FIR filters using time domain approach of the spectral parameter approximation (SPA) technique. Farrow structure is used to implement the SPA-based filter. In the design of variable filters first design the practical filters which satisfy the given transition bandwidth, passband ripple, and stopband attenuation specifications and then approximate the coefficients of these filters by the impulse response of the Farrow structure. Least-squares technique is used to approximation problem. Various design and implementation cases with FPGA synthesis results are presented

Design of complex-valued variable digital filters and its application to the realization of arbitrary sampling rate conversion for complex signals

The 47th Midwest Symposium on Circuits and Systems Conference, Salt Lake City, Utah, USA, 25-28 July 2004This paper studies the design of complex-valued variable digital filters (CVDFs) and their applications to the efficient arbitrary sample rate conversion for complex signals in software radio receivers. The design of CVDFs using either the minimax or least squares criteria is formulated as a convex optimization problem and solved using the second order cone programming (SOCP) or semidefmite programming (SDP). In addition, linear and convex quadratic inequality constraints can be readily incorporated. Design examples are given to demonstrate the effectiveness of the proposed approach.published_or_final_versio

On the minimax design of passband linear-phase variable digital filters using semidefinite programming

Variable digital filters (VDFs) are useful to the implementation of digital receivers because its frequency characteristics such as fractional delays and cutoff frequencies can be varied online. In this letter, it is shown that the optimal minimax design of VDFs with passband linear-phase can be formulated and solved as a semi-definite programming (SDP) problem, which is a powerful convex optimization method. In addition, other objective functions, such as least squares, and linear and convex quadratic inequality constraints can readily be incorporated. Design examples using a variable fractional delay (VFD) and a variable cutoff frequency (VCF) FIR filters are given to demonstrate the effectiveness of the proposed approach. © 2004 IEEE.published_or_final_versio

Waveform Design for 5G and beyond Systems

5G traffic has very diverse requirements with respect to data rate, delay, and reliability. The concept of using multiple OFDM numerologies adopted in the 5G NR standard will likely meet these multiple requirements to some extent. However, the traffic is radically accruing different characteristics and requirements when compared with the initial stage of 5G, which focused mainly on high-speed multimedia data applications. For instance, applications such as vehicular communications and robotics control require a highly reliable and ultra-low delay. In addition, various emerging M2M applications have sparse traffic with a small amount of data to be delivered. The state-of-the-art OFDM technique has some limitations when addressing the aforementioned requirements at the same time. Meanwhile, numerous waveform alternatives, such as FBMC, GFDM, and UFMC, have been explored. They also have their own pros and cons due to their intrinsic waveform properties. Hence, it is the opportune moment to come up with modification/variations/combinations to the aforementioned techniques or a new waveform design for 5G systems and beyond. The aim of this Special Issue is to provide the latest research and advances in the field of waveform design for 5G systems and beyond

Multiple Bandwidth FIR Filter Design with Adaptive Algorithms for Hearing Aid Systems

Digital Filter design plays a vital role in signal processing and communication applications. This paper proposes a hearing loss system model with Variable Bandwidth FIR Filter (VBF) and adaptive algorithms for the application to listening. The tunable band filter is designed to provide an appropriate sound level. This filter has several sub-filters each of which is designed with set of selected bandwidths. The sub-bands obtained are adjusted with proper magnitude by trial and error method. Algorithms such as Least Mean Square (LMS), Normalized Least Mean Square (NLMS) and Recursive Least Squares (RLS) are incorporated to improve the quality of the signal. The filter thus designed is examined by taking a number of audio signals. The tests on various hearing loss cases with different type of input signal suggest that this method is capable of reproducing a signal which sounds exactly the same as the original signal. The multiple bandwidth filters is analyzed with mild, moderate, profound and severe hearing loss patterns and the results are reported. The matching error is calculated between ideal response and actual response. The result show that the designed filter provides acceptable minimum matching error and it lies in the range 0 to 2.5dB.This filter design is implemented in TMS320C6711 processor and is tested for sinusoidal input signal

Multiple Bandwidth FIR Filter Design with Adaptive Algorithms for Hearing Aid Systems

605-623Digital Filter design plays a vital role in signal processing and communication applications. This paper proposes a hearing loss system model with Variable Bandwidth FIR Filter (VBF) and adaptive algorithms for the application to listening. The tunable band filter is designed to provide an appropriate sound level. This filter has several sub-filters each of which is designed with set of selected bandwidths. The sub-bands obtained are adjusted with proper magnitude by trial and error method. Algorithms such as Least Mean Square (LMS), Normalized Least Mean Square (NLMS) and Recursive Least Squares (RLS) are incorporated to improve the quality of the signal. The filter thus designed is examined by taking a number of audio signals. The tests on various hearing loss cases with different type of input signal suggest that this method is capable of reproducing a signal which sounds exactly the same as the original signal. The multiple bandwidth filters is analyzed with mild, moderate, profound and severe hearing loss patterns and the results are reported. The matching error is calculated between ideal response and actual response. The result show that the designed filter provides acceptable minimum matching error and it lies in the range 0 to 2.5dB.This filter design is implemented in TMS320C6711 processor and is tested for sinusoidal input signal