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In-Depth Information
Chapter 12
Analog Filter Design Revisited: Circuit
Configurations Using Newer Varieties of CCs
Abstract This chapter presents some selected universal biquad filter realizations in
Voltage-mode, Current- mode and mixed-mode, using a variety of new types of
CCs reported in the technical literature during the past two decades or more. In each
category, we have chosen only a few representative configurations which, in our
opinion, exhibit features superior to the other available alternatives.
12.1
Introduction
In Chap.
6
of this monograph we have presented significant contributions made by
various researchers in devising universal biquad filter configurations in voltage-
mode (VM) and current-mode (CM) using the normal kind of CCs. The circuits
described therein can, therefore, be practically implemented with the commercially
available IC CCs, for example, by using AD844 (one for CCII+ and two for
CCII
), op-amps uA741/LF356 and transistor arrays CA9086, PA630 or
OPA660/860. Thus, all the circuits described in Chap.
6
are physically realizable
using of-the-shelf IC components.
In the available literature, there exist a large number of other varieties of current
conveyors proposed by various researchers from time to time, which have already
been dealt with in Chap.
10
of this monograph. Although such variants of CCs are
not commercially available as of now, however, if one tries to build them with the
available ICs, it can be done
albeit
at the expense of requiring several such IC
components and passive elements. Since the proposers of such building blocks and
other researchers have also devised a number of CMOS-based hardware
implementations of these, it is obvious that the circuits using such variants of
CCs are implicitly intended and are most suitable for fully-integrated circuit
designs rather than discrete application. Since the circuits using the different
varieties of CCs do offer a number of significant advantages, such as, a reduced
number of active elements employed, greater functionality and improved charac-
teristic features, apart from their suitability for VLSI implementation using bipolar/
CMOS/BiCMOS technologies, they are naturally of considerable interest and
therefore, worth considering for studies and investigations.
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