Charge transfer delay line filters
AssigneeBell Telephone Laboratories, Incorporated
InventorRobert Henry Walden
Life of this patent
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Abstract
A charge transfer analog signal filter is described in which a plurality of charge storage cells are connected in series to form a delay line having a time delay T between its input and output cells. In a feed-forward rejection filter the analog signal is applied to the input cell through a cell of area A.sub.1 and to the output cell through another cell of area A.sub.2. The transfer function of the rejection filter is ##EQU1## In a feedback bandpass filter the analog signal is applied to the input cell through a cell of area A.sub.1, and the output cell is coupled to the input cell through the series combination of an analog inverter and another cell of area A.sub.2. The transfer function of the bandpass filter is ##EQU2##
Claims7
A charge transfer device for filtering an analog signal comprising,
- means including a charge storage medium for forming a delay line including a plurality of charge storage cells formed in said medium, said cells being connected in series with one another and each being of area A, a pair of terminal cells one of which forms the input and the other of which forms the output of said delay line,
- means forming in said medium charge storage control cells of areas A.sub.1 and A.sub.2, where A.sub.1 is different from A.sub.2, and
- means for applying said signal to one terminal cell through one of said charge storage control cells and for applying a delayed version of said signal through the other charge storage control cell to said one terminal cell.
Dependencies are inferred from the claim text.