Adaptive analog signal processing with acoustic charge transport filters

An adaptive algorithm suitable for use with programmable acoustic charge transport (ACT) devices is described. Its performance was demonstrated through computer simulations and hardware experiments. An ACT programmable transversal filter (PTF) includes a GaAs ACT device and supports RF, DC, and digital circuitry. The ACT-based PTF is useful in a wide variety of electronic system engineering problems where it is necessary to dynamically modify the filter function, as required in many adaptive filtering applications. The device is ideally suited for the realization of a least-mean-squares (LMS) adaptive equalizer, where the tap weights are digitally adjusted with an associated microprocessor or dedicated DSP device to achieve adaptive equalization of a wideband analog channel while employing the power and accuracy of digital signal processing. Computer simulations and experimental results using an ACT-based PTF in channel identification and adaptive equalizer configurations are described