An ACT based programmable bandpass filter

An ACT (acoustic charge transport) technology based programmable bandpass filter that provides rapid control of both the center frequency and the bandwidth is described. This filter consists of a number of contiguous bandpass filter channels which are summed together to a common output. The filter response is controlled directly in the frequency domain by selectively switching the input signal at one or more of the individual filter inputs. All filter states are linear phase filters, and the switching time between filter states is typically around 1 μs. This filter has 16 programmable frequency channels of 2 MHz each. The bandwidth can be varied from 2 MHz to 32 MHz within the 54 and 86 MHz range. The various filter states demonstrate selectivities ranging from 45 to 55 dB