Design of a CMOS fully-differential continuous-time tenth-order filter based on IFLF topology

Performance comparison of high-order IFLF and LF linear phase lowpass OTA-C filters with and without gain boost

“…The realizability of arbitrary transmission zeros, regularity and simplicity of the filter structures, and explicit and straightforward formulas available have made the MLF method a strong alternative. MLF OTA-C filters have been used in several applications such as anti-aliasing in video signal processing [10], wireless transceiver baseband channel selection [11][12][13][14], magnetic recording channel equalisation [15,16], linear phase filtering in computer hard disk drive systems [17][18][19][20][21][22][23].…”

A DC stabilized log‐domain nth‐order multifunction filter based on the decomposition of nth‐order HP filter function to FLF topology

“…The technique starts from decomposing the transfer function of nth-order HP filter function into the function block diagram (FBD). The FBD has multiple negative feedback paths from the output and intermediate nodes back to the input, thereby leading to FLF structure with all the above mentioned filter functions available at different nodes at the same time and enjoying all the advantages offered by the designs reported in [19][20][21][22][23][24][35][36][37][38][39][40]. The FBD is first converted into G m -C configuration, which is a voltage-mode representation.…”

“…tuneability, extended dynamic range (DR), and low power consumption while maintaining a good signal-to-noise ratio by virtue of the efficient use of nonlinearity.A persistent attempt has always been carried forward on designing high-order filters both in linear and log-domain realms. There has been overwhelming use of the multiple feedback approach in linear as well as in log-domain fields as it leads to interesting high-order filter topologies [18][19][20][21][22][23][24] that combine the ease of cascaded stage design with sensitivities comparable to active topologies simulating passive LC ladder structures [19,20]. The main configurations of this design technique are follow-the-leader-feedback (FLF), leapfrog and inverse-follow-the-leader-feedback structures, which are of practical interest [21][22][23][24].…”

“…There has been overwhelming use of the multiple feedback approach in linear as well as in log-domain fields as it leads to interesting high-order filter topologies [18][19][20][21][22][23][24] that combine the ease of cascaded stage design with sensitivities comparable to active topologies simulating passive LC ladder structures [19,20]. The main configurations of this design technique are follow-the-leader-feedback (FLF), leapfrog and inverse-follow-the-leader-feedback structures, which are of practical interest [21][22][23][24]. The methods of synthesizing high-order log-domain filters given by Frey [2] and Bernoulli cell [3] based on the cascading of first-and second-order filter sections were ruled out due to the mathematical complexity involved in the exponential synthesis of state-space equations.…”

Synthesis of Leap-Frog Multiple-Loop Feedback OTA-C Filters

“…However, the synthesis of the LF MLF structure is not as simple as the FLF and IFLF structures. While simple explicit formulas exist for the FLF [10], [11] and IFLF [12], [13] configurations that can be easily used [14], an iterative process is required for LF synthesis. As well as general iterative equations, straightforward formulas for the most often used orders of filters should be derived for ready use.…”