共查询到20条相似文献,搜索用时 31 毫秒
1.
Yong Ching Lim Ya Jun Yu Saramaki T. 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(11):2444-2453
Hilbert transformers and half-band filters are two very important special classes of finite-impulse response filters often used in signal processing applications. Furthermore, there exists a very close relationship between these two special classes of filters in such a way that a half-band filter can be derived from a Hilbert transformer in a straightforward manner and vice versa. It has been shown that these two classes of filters may be synthesized using the frequency-response masking (FRM) technique resulting in very efficient implementation when the filters are very sharp. While filters synthesized using the FRM technique has been characterized for the general low-pass case, Hilbert transformers and half-band filters synthesized using the FRM technique have not been characterized. The characterization of the two classes of filter is a focus of this paper. In this paper, we re-develop the FRM structure for the synthesis of Hilbert transformer from a new perspective. This new approach uses a frequency response correction term produced by masking the frequency response of a sparse coefficient filter, whose frequency response is periodic, to sharpen the bandedge of a low-order Hilbert transformer. Optimum masking levels and coefficient sparseness for the Hilbert transformers are derived; corresponding quantities for the half-band filters are obtained via the close relationship between these two classes of filters. 相似文献
2.
Hakan Johansson 《Circuits, Systems, and Signal Processing》2006,25(2):175-200
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. 相似文献
3.
Diniz P.S.R. de Barcellos L.C.R. Netto S.L. 《Signal Processing, IEEE Transactions on》2004,52(5):1278-1288
Due to the growing importance of multichannel modulation, there has been great interest in the design of high-performance transmultiplex systems. In this paper, a new cosine-modulated transmultiplex structure is proposed based on a prototype filter designed with the frequency-response masking (FRM) approach. This new structure leads to substantial reduction in the computational complexity (number of multiplications per output sample) of the prototype filters having sharp transition band and equivalently small roll-off values. The relation between the interpolation factor used in the FRM prototype filter and the decimation factor in the subbands leads to distinct structures. Examples included indicate that the reduction in computational complexity can be higher than 50% of the current state-of-art designs, whereas the reduction on the number of distinct coefficients of the prototype filter can be reduced even further (over 75%). As a result, the proposed approach allows the design of very selective subfilters for transmultiplexes with a very large number of subchannels. 相似文献
4.
Reconfigurable non-uniform channel filters are now being widely used in software define radio (SDR). The hardware implementation of these filters requires low complexity, low chip area and low power consumption. The frequency response masking (FRM) approach is proved to be a good candidate for the realization of a sharp digital finite impulse response (FIR) filter with low complexity. To reduce the complexity further, this paper gives an optimal design method which makes the channel filters totally multiplier-less. This is done in two steps. The channel filters are designed using the FRM approach with continuous filter coefficients. To obtain multiplier-less design, these filter coefficients are converted to finite-precision coefficients using signed power of two (SPT) space and the filter coefficients are synthesized in the canonic signed-digit (CSD) format. But this may lead to degradation of the filter performance. Hence the filter coefficients synthesis in the CSD format is formulated as an optimization problem. Several meta-heuristic algorithms like Differential Evolution (DE), Artificial Bee Colony (ABC), Harmony Search Algorithm (HSA) and Gravitational Search Algorithm (GSA) are modified and deployed and the best one is selected. 相似文献
5.
A very efficient technique to drastically reduce the number of multipliers and adders in narrow transition-band linear-phase
finite-impulse response digital filters is to use the one-stage or multistage frequency-response masking (FRM) approach, which
has been originally introduced by Lim and further improved by Lim and Lian. In these original synthesis techniques, the subfilters
in the overall implementation are separately designed. As shown earlier by the authors of this contribution together with
Johansson, the arithmetic complexity in one-stage FRM filter designs can be considerably reduced by using the following two-step
technique for simultaneously optimizing all the subfilters. First, a suboptimal solution is found by using a simple design
scheme. Second, this solution is used as a start-up solution for further optimization, which is carried out with the aid of
an efficient nonlinear optimization algorithm. This paper exploits this approach to synthesizing multistage FRM filters. An
example taken from the literature illustrates that both the number of multipliers and the number of adders for the resulting
optimized multistage FRM filters are approximately 70 percent compared with those of the filters synthesized using the original
multistage FRM filter design schemes. Additional examples are included in order to show the benefits provided by the proposed
synthesis scheme over other recently published design techniques, in terms of an improved performance of the resulting solution,
a higher accuracy of the solution, and a faster speed required to arrive at the best solution. 相似文献
6.
In this paper, computationally efficient filter structures based on the frequency-response masking (FRM) technique are proposed
for the synthesis of arbitrary bandwidth sharp finite impulse response (FIR) filters. A serial masking scheme is introduced
in the new structures to perform the masking task in two stages, which reduces the complexity of the masking filters. Compared
to the original FRM and interpolated FIR-FRM (IFIR-FRM) structures, the proposed structures achieve additional savings in
terms of numbers of arithmetic operations. 相似文献
7.
Software defined radio (SDR) is emerging as a powerful platform for future generation cellular systems, due to its capability
to operate conforming to multiple mobile radio standards. Channelizer in an SDR operates at the highest sampling rate and
hence a low complexity design is needed for the most computationally intensive part of the SDR receiver. The channel filters
in the channelizer extracts radio channels of varying bandwidths, corresponding to various communication standards from the
wideband input signal. An architecture for implementing low complexity, low power and reconfigurable channel filter for the
SDR mobile handsets, based on multi-stage frequency response masking (FRM) is proposed in this paper. The proposed architecture
is unique in a way that it is able to effectively exploit the redundancy in multi-stage realization by utilizing the common
masking filters and also capable of extracting varying bandwidth channels. Design examples show that the proposed architecture
offers 47.5% complexity reduction and 18.1% power reduction over single-stage FRM approach. 相似文献
8.
Wei Rong Lee Caccetta L. Kok Lay Teo Rehbock V. 《Signal Processing, IEEE Transactions on》2006,54(9):3459-3467
This paper presents a unified approach to the optimal design of sharp linear-phase finite-impulse-response (FIR) digital filters synthesized using the multistage frequency-response masking (FRM) technique. In this approach, the design of a k-stage FRM filter is achieved in a recursive manner. The minimax design problem arising at each step of the synthesis process is converted into a corresponding weighted least-squares (WLS) problem. The WLS problem is highly nonlinear with respect to the coefficients of the filter. Consequently, it is decomposed into several linear least-squares (LS) problems, each of which can be solved analytically. It is then solved iteratively by using an alternating variable approach. Numerical design examples are included to demonstrate the effectiveness of the method. 相似文献
9.
The frequency-response masking (FRM) approach has been introduced as a
means of generating narrow transition band linear-phase finite impulse response (FIR)
filters with a low arithmetic complexity. This paper proposes an approach for synthesizing
two-channel maximally decimated FIR filter banks utilizing the FRM technique. For this
purpose, a new class of FRM filters is introduced. Filters belonging to this class are used
for synthesizing nonlinear-phase analysis and synthesis filters for two types of two-channel
filter banks. For the first type, there exist no phase distortion and aliasing errors, but this
type suffers from a small amplitude distortion as for the well-known quadrature mirror
filter (QMF) banks. Compared to conventional QMF filter banks, the proposed banks lower
significantly the overall arithmetic complexity at the expense of a somewhat increased
overall filter bank delay in applications demanding narrow transition bands. For the second
type, there are also small aliasing errors, allowing one to reduce the arithmetic complexity
even further. Efficient structures are introduced for implementing the proposed filter banks,
and algorithms are described for maximizing the stopband attenuations of the analysis
and synthesis filters in the minimax sense subject to the given allowable amplitude and/or
aliasing errors. Examples are included illustrating the benefits provided by the proposed
filter banks. 相似文献
10.
Yong Ching Lim Rui Yang 《Signal Processing, IEEE Transactions on》2005,53(4):1387-1397
Decimation and interpolation are very common multirate signal processing operations. Conventional decimation or interpolation technique using polyphase filters has the advantage that for a given transition-band sharpness, the filter's computational complexity decreases with increasing interpolation or decimation factor. Nevertheless, if the transition band of the decimation or interpolation filter is very sharp, the complexity of the filter may still be very high. The complexity of a very sharp filter may be reduced using the frequency-response masking (FRM) technique. However, as shown in this paper, for a given transition-band sharpness, the computational complexity of the classical FRM method does not reduce as rapidly as the increase in decimation or interpolation factor. In this paper, we present a novel variant of the FRM technique for interpolation or decimation application. In this new variant, the computational complexity reduces as rapidly as the interpolation or decimation factor increases. The reduction in computational complexity increases with decreasing transition width. Over an order of magnitude reduction in computational complexity is achieved when compared with conventional polyphase approach in a particular example presented in this paper. 相似文献
11.
A new method to reduce the number of arithmetic operations in a sharp FIR filter
synthesized by the frequency-response masking (FRM) technique is presented. The success
of the proposed method is based on a modified FRM approach where the subfilters in
the FRM approach are implemented by using recently introduced prefilter-equalizer based
filters. It is shown, by means of examples, that the proposed method yields considerable
savings in the numbers of multipliers and adders compared to the original single-stage
FRM approach. 相似文献
12.
This paper offers two main contributions to the theory of low-delay frequency-response masking (FRM) finite impulse response
(FIR) filters. First, a thorough investigation of the low-delay FRM FIR filters and their subfilters or three different structures,
referred to as narrow-, wide-, and middle-band filter structures, is given. The investigation includes discussions on delay
distribution over the subfilters as well as estimation of the optimal periodicity of the periodic model filter. Second, systematic
design procedures are given, with explicit formulas for distribution of the ripples and the delay to the subfilters. For each
of the three structures, two design procedures are given that include joint optimization of the subfilters. The first proposal
uses partly linear-phase FIR subfilters and partly low-delay FIR subfilters. Thus, it has a lower arithmetic complexity compared
to the second proposal, which has exclusively low-delay FIR subfilters. The second proposal is instead more flexible and can
handle a broader range of specifications. The design procedures result in low-delay FIR filters with a lower arithmetic complexity
compared to previous results, for specifications with low delay and narrow transition band. 相似文献
13.
Mahesh R. Vinod A.P. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2008,55(3):274-278
Low complexity and reconfigurability are two key requirements of channel filters in a software defined radio receiver. A new reconfigurable architecture based on frequency response masking (FRM) technique for the implementation of channel filters is proposed in this paper. Our architecture offers reconfigurability at filter and architecture levels, in addition to the inherent low complexity offered by the FRM technique. The proposed reconfigurable filter has been synthesized on 0.18- CMOS technology and implemented and tested on Virtex-II 2v3000ff1152-4 field-programmable gate array. Synthesis results show that the proposed channel filter offers average area and power reductions of 53.6% and 57.6%, respectively ,with average improvement in speed of 47.6% compared to other reconfigurable filters in literature. 相似文献
14.
15.
Design of Computationally Efficient Sharp FIR Filter Utilizing Modified Multistage FRM Technique for Wireless Communications Systems 下载免费PDF全文
Modern wireless communications gadgets demand multi-standard communications facilities with least overlap between different input radio channels. A sharp digital filter of extremely narrow transition-width with lower stop band ripples offers alias-free switching among the preferred frequency bands. A computationally competent low pass filter (LPF) structure based on the multistage frequency response masking (FRM) approach is proposed for the design of sharp finite impulse response (FIR) filters which are suitable for wireless communications applications. In comparison of basic FRM with other existing multistage FRM structures, the proposed structure has a narrow transition bandwidth and higher stop band attenuation with significant reduction in terms of the number of computational steps. A design example is incorporated to demonstrate the efficiency of the proposed approach. Simulation results establish the improvement of the proposed scheme over other recently published design strategies. 相似文献
16.
Lee W.R. Caccetta L. Teo K.L. Rehbock V. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2006,53(5):379-383
This paper presents an application of the weighted least squares (WLS) method to the design of sharp linear phase finite-impulse response (FIR) digital filters synthesized using a modified frequency-response masking (FRM) structure. In our approach, the original minimax design problem is converted into a WLS problem. The WLS problem is highly nonlinear with respect to the coefficients of the filter. However, it can be decomposed into four linear least squares (LS) problems, each of which can be solved analytically. The design problem is then solved iteratively by using an alternating variable approach. The effectiveness of the method is demonstrated through solving a low-pass linear phase sharp FIR digital filter example. 相似文献
17.
18.
Luiz C. R. de Barcellos Sergio L. Netto Paulo S. R. Diniz 《Circuits, Systems, and Signal Processing》2003,22(2):99-113
This paper presents efficient methods for designing linear-phase finite impulse
response filters by combining the frequency-response masking (FRM) approach and the
weighted least-squares (WLS)-Chebyshev method. We first use the WLS-Chebyshev
method to design quasi-equiripple FRM filters, achieving better performances with respect
to the passband ripple or the stopband attenuation, when compared with the standard
FRM design. Then, by exploiting the concept of critical bands, introduced in this paper,
we present a method for designing modified FRM filters with a further reduction in the
computational complexity. This is achieved by properly relaxing the specifications for the
FRM base and masking filters and using the ability of the WLS-Chebyshev method to trade
off the minimum attenuation and the total energy in the filters stopband. Computational
savings are in the order of 10%–15% of the original number of coefficients of the standard
FRM design (using the concept of dont care bands for the masking filters). 相似文献
19.
Yongzhi Liu Zhiping Lin 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(6):1560-1570
20.
针对FIR滤波器设计中锐截止宽带滤波器阶数较高、计算复杂的问题,提出用频率掩蔽法,先设计一个过渡带为目标过渡带的L倍的原型滤波器,其实现复杂度远小于所要求的滤波器,依据L倍内插滤波器的过渡带宽是原型滤波器的1/L的原理,利用一对互补滤波器和掩蔽滤波器,得到了较低计算复杂度的锐截止宽带滤波器。 相似文献