Design of frequency agile filters in RF frontend circuits

Design of CDTA and VDTA Based Frequency Agile Filters

“…The proposed filter uses grounded resistor which can easily be implemented using the TA with transconductance equal to 3 based structure given in Figure 9. To realize second order filter, Bias7 is set to value of Bias4 such that 7 is equal to 4 and Bias6 is set to value such that 6 is equal to sum of 3 and 4 ; that is, 6 = 3 + 4 . Consider…”

“…Practically, the designs employ either elements handling various standards in parallel or reconfigurable elements. The frequency agile filter (FAF) [1][2][3][4][5][6][7][8][9][10] characterized by adjustment range, reconfigurability, and agility may be used in transceivers. The term shadow filters is sometimes used in literature to refer to FAF [11,12].…”

“…The term shadow filters is sometimes used in literature to refer to FAF [11,12]. The literature survey shows that a limited number of topologies of active FAF are available and are based on op-amp [1] and current mode active block [2,3] and CMOS [4].…”

Realization of CDTA based frequency agile filter

“…The recently introduced frequency agile filter (FAF) [1]- [10] may be used in transceivers and is characterized by adjustment range; reconfigurability against tunability, and agility. The literature survey shows that a limited number of topologies of active FAF are available and are based on opamp [1] and current mode active block [2]- [3] and CMOS [4].…”