An efficient closed-form approach to the design of linear-phase FIR digital filters with variable-bandwidth characteristics

Linear-Phase VDF Design With Unabridged Bandwidth Control Over the Nyquist Band

“…It can be observed that the SPA-MCDM-VDF requires fewer VMs than VDFs in [2], [6], and [10], and this difference in VMs increases as T BW d decreases particularly in the case of [6] and [2]. This means that the SPA-MCDM-VDF will offer further savings in implementation complexity over [6].…”

“…For the first design example discussed in Section IV, SPA-VDF [10] consists of 16 subfilters, each of order 62. The SPA-VDF in [11] consists of two sets of subfilters to obtain LP responses in the first and second quarters.…”

“…Each set consists of five subfilters of order 32. To obtain BP and BS responses, SPA-VDFs [10], [11] need two branches of VMs. Since the MCDM-VDF [14] provides only coarse control over the cutoff frequency, the resolution between cutoff frequencies is fixed at 0.02π.…”

“…The SPA-MCDM-VDF requires 73%, 17.5%, 78%, and 10% lower gate count than that of SPA-VDF [10], SPA-VDF in [11], MCDM-VDF [14], and MFT-VDF [6], respectively, for the first design example. Similar savings are also achieved in the case Table II.…”

Design and FPGA Implementation of Reconfigurable Linear-Phase Digital Filter With Wide Cutoff Frequency Range and Narrow Transition Bandwidth

“…Subsequently, to overcome these disadvantages of variable coefficient filters, reconfigurable filters are developed in which fc is varied using only a couple of variable parameters by modifying the impulse response of the fixed-coefficient prototype filter. One of the techniques of reconfigurable digital filter design, the spectral parameter approximation (SPA) technique [3][4][5][6][7][8][9][10], provides absolute control over fc. The SPA technique has also been combined with other techniques to design reconfigurable filters [11,12].…”