Recent Advances in Binary-Programmed Electronically-Tunable Bandpass Filters of the "Flauto" Type

Two half-wave resonators with binary-programmed, high-speed electronic tuning have been cascaded to form a second-order high-power bandpass filter for the range 355 to 400 MHz. Seven binary-scaled, PIN-diode-controlled, tuning irises in each resonator provide a maximum tuning increment of 550 kHz while the tracking error never exceeds 150 kHz. Extensive improvements were made in design and performance, and in automatic control and testing, over previous work with a single resonator of more primitive design.