Heterojunction acoustic-charge-transport fixed-tap transversal filter

Abstract

A heterojunction acoustic-charge-transport (HACT) transversal filter with a 3.35-fis-long array of output electrodes was designed, fabricated, and evaluated. The device operated at an acoustic clock frequency of 143.6 MHz with a charge transfer efficiency in excess of 0.9999. The impulse response and swept frequency response of the device were nearly ideal. Based upon measurements of the 1-dB compression point, the third-order intercept, and the noise floor of the device, a thermal dynamic range of 80 dB and a spurious free dynamic range of 62 dB were demonstrated over a 3M-kHz bandwidth. The device exhibited 12 dB of gain when embedded in a 5 0 4 system.