Heterojunction acoustic-charge-transport fixed-tap transversal filter

A heterojunction acoustic-charge-transport (HACT) transversal filter with a 3.35- mu s-long array of output electrodes is discussed. 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. On the basis of 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 300-kHz bandwidth. The device exhibited 12 dB of gain when embedded in a 50- Omega system. >