Continuously Variable Bandwidth Sharp FIR Filters with Low Complexity

James T. George, Elizabeth Elias

National Institute of Technology.

DOI: 10.4236/jsip.2012.33040                

Abstract

In software defined radio (SDR), sharp filters of different bandwidth are required to fine tune the desired channel. This requires different computational resources and large number of filter coefficients. This paper proposes a continuously variable bandwidth sharp finite impulse response (FIR) filter with low distortion and low complexity. For this, a fixed length FIR filter is used with two arbitrary sampling rate converters. This system can be used for both the continuous increase as well as decrease of the effective bandwidth of a filter. The low complexity and sharpness are achieved by using the frequency-response masking (FRM) approach for the design of the fixed length FIR filter. The sharp transition width leads to maximum rejection to channel interference in SDR.

Keywords

Variable Bandwidth Filter; Frequency-Response Masking; Low Complexity; Finite Impulse Response Filter; Re-Sampling

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Y. J. Yn, Y. C. Lim and D. Shi, “Low-Complexity Design of Variable Bandedge Linear Phase FIR Filters with Sharp Transition Band,” IEEE Transactions on Signal Processing, Vol. 57, No. 4, 2009, pp. 1328-1338.
[2]	H. Johansson, “On Linear Phase FIR Filters with Variable Bandwidth,” IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 51, No. 4, 2004, pp. 181-184.
[3]	R. Mahesh and A. P. Vinod, “Reconfigurable Frequency Response Masking Filters for Software Radio Channelization,” IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 55, No. 3, 2008, pp. 274-278.
[4]	C. W. Farrow, “A Continuously Variable Digital Delay Element,” IEEE International Symposium on Circuits and Systems, Espoo, 7-9 June 1988, pp. 2641-2645.
[5]	A. V. Oppenheim, W. F. G. Mecklenbrauker and R. M. Mersereau, “Variable Cutoff Linear Phase Digital Filter,” IEEE Transactions on Circuits and Systems, Vol. 23, No. 4, 1976, pp. 199-203.
[6]	S. Roy and S. S. Ahuja, “Frequency Transformations for Linear-Phase Variable-Cutoff Digital Filters,” IEEE Transactions on Circuits and Systems, Vol. 26, No. 1, 1979, pp. 73-75.
[7]	F. Harris, “Selectable Bandwidth Filter Formed from Perfect Reconstruction Polyphase Filter Bank,” 2010 Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers, Pacific Grove, 5-7 November 2010, pp. 1292-1296. doi:10.1109/ACSSC.2010.5757740
[8]	R. Mahesh and A. P. Vinod, “Reconfigurable Low Area Complexity Filter Bank Architecture Based on Frequency Response Masking for Nonuniform Channelization in Software Radio Receivers,” IEEE Transactions on Aerospace and Electronic Systems, Vol. 47, No. 2, 2011, pp. 1241-1255. doi:10.1109/TAES.2011.5751255
[9]	F. Harris, “Fixed Length FIR Filters with Continuously Variable Bandwidth,” 1st International Conference on Wireless Communication, Vehicular Technology, Information Theory and Aerospace & Electronic Systems Technology, Aalborg, 17-20 May 2009, pp. 931-935.
[10]	F. J. Harris, “Multirate Signal Processing for Communication Systems,” Prentice Hall, Upper Saddle River, 2004.
[11]	P. P. Vaidyanathan, “Multirate Systems and Filter Banks,” Englewood Cliffs, Prentice Hall, 1993.
[12]	Y. Lim, “Frequency-Response Masking Approach for the Synthesis of Sharp Linear Phase Digital Filters,” IEEE Transactions on Circuits and Systems, Vol. 33, No. 4, 1986, pp. 357-364.
[13]	T. Saramaki and Y. C. Lim, “Use of the Remez Algorithm for Designing FRM Based FIRr Filters,” Circuits, Systems, and Signal Processing, Vol. 22, No. 2, 2003, pp. 77-97. doi:10.1007/s00034-004-7021-5
[14]	Y. Wei and Y. Lian, “Frequency-Response Masking Filters Based on Serial Masking Schemes,” Circuits, Systems, and Signal Processing, Vol. 29, No. 1, 2010, pp. 7- 24.