At the very beginning of the filter design, an appropriate filter transfer function and the order of the filter have to be selected. In radio receivers, the bandwidth and, particularly, the selectivity requirement for channel-select and anti-aliasing filtering are determined by the wireless application being targeted, the specified or expected interferers scenario, and the performance of the ADC, as discussed in Chap. 2. The bandwidth and selectivity requirements of the analog baseband filter further depend on the receiver architecture adopted and the preceding filter stages. The filter transfer function and the order of the filter are then chosen according to the given selectivity requirement. In addition, for example, the passband flatness and phase response characteristics that are required have to be taken into account. In active filter implementations, the minimization of filter stages (i.e. the order of the filter) is typically beneficial in terms of noise, power consumption, and complexity. Therefore, it is important also to consider the feasibility of the active filter realization, as well as the performance requirements set for the filter block, before finally deciding on the filter prototype.The next step is to synthesize the filter realizing the selected transfer function. Broadly speaking, there are two dominant approaches to synthesizing active continuous-time filters [1][2][3]. Active filters can be realized by biquads connected in a cascade in which each biquad implements a complex pole pair (with or without zeros) of the transfer function. Another approach is to simulate the operation of an LC ladder prototype filter. Lossless doubly terminated LC ladder filters are able to realize a large number of conventional filter transfer functions, such as Butterworth, Chebyshev, and Elliptic approximations. In addition, they are known to have a low sensitivity in their passband frequency response to component value variations [1][2][3][4][5][6][7][8][9][10][11]. The operation of LC ladder filters can be simulated with active filter realizations in such a way that a one-to-one correspondence between the reactive elements of the LC ladder and the integrators of the corresponding active realization is maintained [5,8]. As a result, these active filters inherit the low-sensitivity behavior [1-3, 5, 6, 8, 10-13]. Considering the operational simulation of LC ladder filters, the signal flow graph (SFG) method is one of the most widely used V. Saari et al.,
