HACT device applications

Heterojunction acoustic charge transport (HACT) transversal filters have been successfully operated with a charge transport efficiency of 0.9996 for 6- mu s devices and >0.9999 for 3.3 mu s devices with uniform tap weighting. Device delays in excess of 10 mu s should be possible. Results for HACT devices with apodized tap weights are presented and demonstrate accurate time and frequency response characteristics. Hamming filter sidelobes are close to theory. Phase weighting of HACT taps resulted in excellent device-matched filter response to a nested Barker code input. Transversal equalization or pulse sharpening, is demonstrated for an exponential input, reflecting the good baseband response of the device.<
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