Broad-band band-pass filter with variable center frequency and band width

This paper describes a new type of broad-band band-pass filter in which both the center frequency and band width are variable. The filter is composed of four balanced mixers, two local oscillators, an amplifier, and high-pass and low-pass filters. The center frequency and band width can be varied by changing the frequencies of two local oscillators. The center frequency is variable in the range 2–16 GHz, and the band width in the range 20–800 MHz.