Design of Switched-Capacitor and Wave Digital Filters with Linear Phase and
Hussein Baher, Mark J O'Malley · 1990
A design technique, and the associated algorithm, are pre- sented for selective linear-phase low-pass and high-pass sampled-data filters. The resulting filter transfer functions are particularly suitable for realization as leap-frog lossless discrete integrator (LDI) switched- capacitor structures and also in wave digital form. Due to the specific form of the transfer function, the filters generally have no lumped-ele- ment counterparts. The technique leads to an optimum compromise between amplitude selectivity and passband phase linearity under the restriction of a prescribed form of the transfer function, and allows the use of finite jw-axis zeros of transmission for achieving high amplitude selectivity. The transfer functions presented are also capable of realiza- tion as distributed microwave filters, hut these require the use of coupled-wire networks in the form of distributed Brune sections, if jw -axis zeros of transmission are introduced.