Charge transfer filter has devices connected as loop - with configuration designed to avoid topological crosspoints

摘要

The charge transfer filter has its charge transfer devices connected into loops to form resonant circuits as in 2453669. In order to make the filter more readily realisable as an integrated circuit (e.g. by avoiding topological crosspoints and by minimising the number of amplifiers per resonant circuit), each input (1, 4) and output (2, 3) consists of several short CTD lines (20, 21, 22) forming a -network with the associated amplifier (30) in one corner. Each -network has its legs joined by a shunt CTD line (5', 5"). These two shunt lines are joined by two further series lines (5).