Interpolated FIR Research Articles

Design and implementation of Pulse-Shaping FIR Interpolation filter using BCSE Algorithm

Design and implementation of Pulse-Shaping FIR Interpolation filter using BCSE Algorithm

Computer Aided BER Performance Analysis of FBMC Cognitive Radio for Physical Layer Under the Effect of Binary Symmetric Radio Fading Channel

The wireless communication has undergone a revolution due to advancements in technology. For each new user or application to be a part of communication network the preliminary requirement is the allocation of frequency spectrum band. This frequency band is a limited resource and it is impossible to expand its boundaries. So the need is to employ intelligent, adaptive and reconfigurable communication systems which can investigate the requiremenmts of the end user and assign the requisite resources in contrast to the traditional communication systems which allocate a fixed amount of resource to the user under adaptive, autonomic and opportunistic cognitive radio environment. Cognitive radio technology has emerged from software defined radios wherein the key parameters of interest are frequency, power and modulation technique adopted. The role of cognitive radio is to alter these parameters under ubiquitous situations. The spectrum sensing is an important task to determine the availability of the vacant channels to be utilised by the secondary users without posing any harmful interference to the primary users. In multi carrier communication using digital signal processing techniques, filter bank multi carrier has an edge over other technologies in terms of bandwidth and spectral efficiency. The present paper deals with the multi rate FIR decimation and interpolation filter approach for physical layer of cognitive radio under binary symmetric fading channel environment.

Performance Analysis of Filter Bank Multicarrier Cognitive Radio for Physical Layer under Binary Symmetric Radio Fading Channel

The wireless communication has undergone a revolution due to advancements in technology. For each new user or application to be a part of communication network the preliminary requirement is the allocation of frequency spectrum band. This frequency band is a limited resource and it is impossible to expand its boundaries. So the need is to employ intelligent, adaptive and reconfigurable communication systems which can investigate the requirements of the end user and assign the requisite resources in contrast to the traditional communication systems which allocate a fixed amount of resource to the user under adaptive, autonomic and opportunistic cognitive radio environment. Cognitive Radio(CR) Technology has emerged from software defined radios wherein the key parameters of interest are frequency, power and modulation technique adopted. The role of Cognitive Radio is to alter these parameters under ubiquitous situations. The Spectrum Sensing is an important task to determine the availability of the vacant channels to be utilised by the secondary users without posing any harmful interference to the primary users. In Multicarrier Communication using Digital Signal Processing Techniques, Filter Bank Multi Carrier has an edge over other technologies in terms of Bandwidth and Spectral Efficiency. The present paper deals with the Multi Rate FIR Decimation and Interpolation Filter approach for physical layer of Cognitive Radio under Binary Symmetric fading channel environment.

BER Performance Analysis of Filter Bank Multicarrier Using Sub band Processing for Physical Layer Cognitive Radio

Cognitive Radio (CR) Technology has emerged from software defined radios wherein the key parameters of interest are frequency, power and modulation technique adopted. The role of Cognitive Radio is to alter these parameters under ubiquitous situations. The Spectrum Sensing is an important task to determine the availability of the vacant channels to be utilized by the secondary users without posing any harmful interference to the primary users. In Multicarrier Communication using Digital Signal Processing Techniques, Filter Bank Multi Carrier has an edge over other technologies in terms of Bandwidth and Spectral Efficiency. The present paper deals with the Multi Rate FIR Decimation and Interpolation Filter along with Usage of two band Analysis and Synthesis sub band processing approach for physical layer of Cognitive Radio under fading channel environment.

A design of IFIR prototype filter for Cosine Modulated Filterbank and Transmultiplexer

This paper proposes a computational efficient approach for the design of M-band Cosine Modulated Filterbank (CMFB) and Transmultiplexer (TMUX) in Near Perfect Reconstruction (NPR) condition. The required prototype filter is formulated by using interpolated FIR (IFIR) technique. Suitable stretch factor is used for the reduction in computation cost and obtained minimum value of distortion parameters. The minimization of these parameters has been achieved by applying a single variable bisection type optimization technique. Design examples are included to prove superiority of performance over the existing work.

Low Complexity Filter Architecture for ATSC Terrestrial Broadcasting DTV Systems

This paper presents a low complexity partially folded architecture of transposed FIR filter and cubic B-spline interpolator for ATSC terrestrial broadcasting systems. By using the multiplexer, the proposed FIR filter and interpolator can provide high clock frequency and low hardware complexity. A binary representation method was used for designing the high order FIR filter. Also, in order to compensate the truncation error of FIR filter outputs, a fixed-point range detection method was used. The proposed partially folded architecture was designed and implemented with 90-nm CMOS technology that had a supply voltage of 1.1V. The implementation results show that the proposed architectures have 12% and 16% less hardware complexity than the other kinds of architecture. Also, both the filter and the interpolator operate at a clock frequency of 200MHz and 385MHz, respectively.

Averaged Lagrange Method for interpolation filter

This paper presents a new method for Lagrange interpolation for reducing distortions without introducing any complexity. The aim is to improve the linearity of the phase and the gain responses of the interpolation filter by an averaging method. A first FIR interpolation filter of the second order computes the values between three successive samples of the input signal. At the same time, a second filter, identical to the first, computes the values between (xk–2 , xk–1 , xk ). Finally, the common values between (xk–2 , xk–1 ) provided by the two filters are averaged two by two. This double interpolation can be simply done with a single third order filter and with a Farrow structure filter. Compared to the usual Lagrange's third order interpolation filter, the behaviour of the filter we propose is more regular especially in the high frequencies of the Nyquist band. More, the filter coefficients are easier to calculate. The designed filter is tested on a FPGA of Altera. The results shows that the method significantly reduces distortions and improves quality of the frequency response.

Two Classes of Frequency-Response Masking Linear-Phase FIR Filters for Interpolation and Decimation

This paper introduces two classes of frequency-response masking (FRM) linear-phase finite (length) impulse response (FIR) filters for interpolation and decimation by arbitrary integer factors M. As they are based on the FRM approach, the proposed filters are low-complexity (efficient) sharp-transition linear-phase FIR interpolation and decimation filters. Compared to previously existing FRM linear-phase FIR filter classes for interpolation and decimation, the new ones offer lower complexity and more freedom in selecting the locations of the passband and stopband edges. Furthermore, the proposed classes of FRM filters can, as special cases, realize efficient Mth-band FRM linear-phase FIR interpolation and decimation filters for all values of M. Previously, only half-band (M = 2) FRM linear-phase FIR filters have appeared in the literature. The paper includes design techniques suitable for the new filters and design examples illustrating their efficiency.

1:4 interpolation FIR filter

A new 1:4 interpolation FIR filter is presented. Using the symmetries of the filter coefficients and the contents of the lookup table (LUT), the two filters for in-phase (I-phase) and quadrature-phase (Q-phase) share the LUT and activate only the selected part of the LUT. Experimental results show that the proposed filter reduces the power consumption and the gate area by 28 and 5% compared to conventional filters.

Method for narrowband minimum phase filter design

A method for narrowband minimum phase filter design, based on the interpolated FIR (IFIR) structure and the mipizing, is proposed. The interpolator in the IFIR structure is a sharpened comb filter. It is shown that this filter is of the minimum phase type, and that consequently mipizing needs to be applied to the shaping filter only.

Area-efficient pulse-shaping 1:4 interpolated FIRfilterbased on LUT partitioning

The design of an area-efficient pulse-shaping 1:4 interpolation FIR filter with a partitioned LUT structure is described. Since the LUT block of the FIR filter occupies a large area relative to that of other blocks, in the proposed FIR filter design the LUT size is reduced by partitioning, exploiting coefficient symmetry, and sharing the partitioned LUTs by multiplexing input data streams. Experiments show that in the proposed filter the area is reduced by >40% compared to the popular single-architecture dual-channel filter. The proposed FIR filter produces optimised results in the QPSK modulator.

Oversampling PCM techniques and optimum noise shapers for quantizing a class of nonbandlimited signals

We consider the efficient quantization of a class of nonbandlimited signals, namely, the class of discrete-time signals that can be recovered from their decimated version. The signals are modeled as the output of a single FIR interpolation filter (single band model) or, more generally, as the sum of the outputs of L FIR interpolation filters (multiband model). These nonbandlimited signals are oversampled, and it is therefore reasonable to expect that we can reap the same benefits of well-known efficient A/D techniques that apply only to bandlimited signals. We first show that we can obtain a great reduction in the quantization noise variance due to the oversampled nature of the signals. We can achieve a substantial decrease in bit rate by appropriately decimating the signals and then quantizing them. To further increase the effective quantizer resolution, noise shaping is introduced by optimizing prefilters and postfilters around the quantizer. We start with a scalar time-invariant quantizer and study two important cases of linear time invariant (LTI) filters, namely, the case where the postfilter is the inverse of the prefilter and the more general case where the postfilter is independent from the prefilter. Closed form expressions for the optimum filters and average minimum mean square error are derived in each case for both the single band and multiband models. The class of noise shaping filters and quantizers is then enlarged to include linear periodically time varying (LPTV)/sub M/ filters and periodically time-varying quantizers of period M. We study two special cases in great detail.

Interpolation of erasure bursts via cosine-modulated filterbanks

A novel and low-complexity approach for reconstructing periodic erasure bursts in data sampled at greater than the Nyquist rate, using cosine modulated filterbanks, is described. In the case of interpolation of erasure singlets or doublets periodically repeated over 2M samples, the cosine modulated filterbank approach is shown to have a lower complexity (for a given restoration error) than a standard FIR interpolator. In the case of erasure triplets or quadruplets, periodically repeated over 2M samples, the restoration error is primarily related to whether theM-channel filterbank’s stopband suppression is better than the condition number of a 2 × 2 matrix, whereM is determined by the oversampling factor of the data. While the method used for erasure triplets and quadruplets extends to arbitrary erasure bursts, the condition numbers of the associated (larger dimension) matrices deteriorate rapidly with the increase in erasure length, posing practical problems such as the design of very high-attenuation filterbanks and large required implementation wordlengths.

Lowpass minimum phase filter design using IFIR filters

A design procedure for minimum-phase FIR filters using an interpolated FIR (IFIR) filter is proposed. The IFIR technique allows two linear-phase filters of much lower order to be designed thereby making it easier to apply mipizing than is possible in high order FIR prototype filters. In this way, the problem of finding the roots of high order polynomials is overcome.

Two-dimensional IFlR structures using generalized factorizable filters

In this paper we extend the idea of interpolated FIR (IFIR) filters to the two-dimensional (2-D) case. IFIR filters make for the reduction of the computational weight, in the one-dimensional (1-D) case as well as in the 2-D case. In the 1-D case, the justification to such a performance advantage rests upon the relationship between filter order, transition bandwidth and minimax errors for equiripple linear-phase filters. Even though no similar relation is known for minimax, optimal multidimensional filters, a qualitatively parallel behaviour is shared by a class of suboptimal filters ("Generalized Factorizable") recently introduced by Chen and Vaidyanathan, for which an efficient implementation exists. In our scheme, we use Generalized Factorizable filters for both the stages of the IFIR structure. An interesting problem peculiar to the multidimensional case is the choice of the sublattice which represents the definition support of the first-stage (shaping) filter. We present a strategy to choose (given the spectral support of the desired frequency response) the optimal sublattice, and to design the second-stage (interpolator) filter in order to achieve low overall computational weight.

EFFICIENT DECIMATOR AND INTERPOLATOR ARRAY STRUCTURES

New and efficient array processor implementations of polyphase FIR and IIR decimators and interpolators, with integer compression and expansion factors, are derived using an algebraic mapping technique. The technique is based on the time-domain representation of the algorithms. It has the merit of being suitable for describing multirate algorithms. The control signals necessary to implement the polyphase structures are explicitly identified. Different array structures are derived in which the inputs are broadcast or pipelined and outputs are pipelined or added simultaneously. Upper bounds on the input/output processing rates are provided in terms of system parameters and hardware delays. The work is extended to map decimators/interpolators with fractional compression/expansion factors onto systolic hardware structures. The new structures have the advantages of being modular, regular, hierarchical, and pipelined.

Design and efficient implementations of predictive FIR filters

Two new approaches to the design of predictive FIR filters are presented. First, we discuss the design of predictors and estimators for narrow-band signals based on the interpolated FIR (IFIR) filter approach. The transfer function of the IFIR predictor is of the form H(z)=P(z/sup L/)G(z) where P(z) is a predictor and G(z) is an interpolating estimator. The general-purpose design procedure for efficient IFIR predictors is described, and demonstrated for polynomial predictors. The resulting predictors, optimized for white noise attenuation, have much lower computational complexity than the corresponding direct-form FIR predictors. Secondly, an IIR filter-based implementation of sinusoidal FIR predictors is presented. As an application, a zero-crossing detector for 50 Hz thyristor drives is designed. >

FIR and IIR SC interpolation filters using parallel cyclic‐type circuit for high frequency

AbstractHigh‐frequency responses of switched‐capacitor filters deteriorated mostly as a result of the finite gain bandwidth product of an operational amplifier. the authors previously proposed a type of FIR and IIR switched‐capacitor filter using a parallel cyclic‐type circuit in order to improve high‐frequency performance. In the parallel cyclic‐type circuit, an operational amplifier is not used as a delay element. Instead, both delay and weighting operations are implemented with switches and a coefficient capacitor simultaneously. Only one operational amplifier is used for a summing operation. Consequently, the maximum operational frequency of the filter is extended up to the unity gain frequency of the operational amplifier.This paper proposes a new type of FIR and IIR switched‐capacitor interpolation filter that can be operated in a high‐frequency region by using the parallel cyclic‐type circuit. Effects of both the finite gain bandwidth of the operational amplifier and parasitic capacitances on filter performance are analyzed by applying the analysis method of periodically time‐varying digital filter. These effects are found to be very few in number below the unity gain frequency of the operational amplifier. Third‐order FIR and biquadratic IIR interpolation filters are constructed with discrete components and verified to have good frequency performance that coincides with the analyzed one.

B-spline FIR filters

This paper presents an efficient procedure for the design of interpolated FIR (IFIR) filters with linear phase. The algorithm uses the uniform B-spline function as an interpolator and solves the optimal Chebyshev approximation problem on the optimal subinterval. The technique can be used for the design of general lowpass, highpass and bandpass filters. While the number of multiplications of the IFIR filter is dependent on the bandwidth and the center frequency of the desired filter, it provides the minimum number of multiplications achievable and nearly always provides a substantial reduction when compared to Parks-McClellan designs.

Systolic implementation of FIR decimators and interpolators

An algebraic technique for mapping FIR decimator and interpolator algorithms with integer compression/expansion factors on systolic and semisystolic structures is described. The technique is based on the time-domain representation of the algorithms. The advantages of this technique are that it is suitable for describing multirate algorithms and that the required arithmetic operations are explicitly stated. Applying the algebraic technique, various structures can be obtained in which the number of multipliers is reduced in proportion to the decimation or interpolation factor. Pipelining can be introduced at the input and/or the output. An example is given to illustrate the flexibility and simplicity of the proposed technique.