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AssigneeSiemens Aktiengesellschaft
InventorsKarl Knauer, Max Schlichte, Hans-Joerg Pfleiderer
Estimating the term…
In illustrated embodiments, at least one analogue shift register has a number of parallel inputs and one series output. A number of individual evaluating circuits receive the signal to be filtered and supply respective output quantities of charge equal to the product of the difference between the relevant signal value and a predetermined minimum or maximum value, and a respective individual evaluation factor. The output of each evaluating circuit can be connected via a switching element to an associated parallel input. The capacity of every storage position of the shift register is at least such that it is always able to accommodate the maximum quantity of charge supplied by the preceding storage position, and when the storage position has a parallel input, can additionally accommodate the maximum quantities of charge supplied by the associated evaluating circuit (s). Various modifications are disclosed for reducing the space requirement of a transversal filter when implemented, for example, as a CCD.
A transversal filter comprising analogue shift register means having successive storage positions, said shift register means having a number of parallel inputs and comprising input charge receiving storage positions having the respective parallel inputs assigned thereto, and said shift register means having a common output, a further number of individual predeterminable evaluating circuit means each having at least one signal input for the input of the signal which is to be filtered, and at least one output, each evaluating circuit means being arranged to weight the input signal thereto in accordance with an individual evaluation factor for producing at its output a weighted charge for supply to an associated input charge receiving storage position, switching element means controlling coupling of the outputs of the evaluating circuit means with the respective assigned parallel inputs for supplying the weighted charges to respective input charge receiving storage positions via the respective assigned parallel inputs, each storage position of the shift register being at least such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position, and each input charge receiving storage position being such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position and additionally able to accommodate the maximum quantity of charge supplied via its assigned parallel input, and said filter being further characterized in that the evaluating circuit means comprises first evaluating circuits (21-24, FIG. 7) having first signal inputs thereto, and comprises second evaluating circuits (25-28, FIG. 7) having respective second signal inputs for receiving an input signal to be filtered, and in that the first signal input of every first evaluating circuit is preceded by a time delay element (800) which delays the input signal thereto relative to the input signal received by said second signal inputs by the length of time required for a quantity of charge to pass through the shift register means during the shift process.
A transversal filter comprising analogue shift register means having successive storage positions, said shift register means having a number of parallel inputs and comprising input charge receiving storage positions having the respective parallel inputs assigned thereto, and said shift register means having a common output, a further number of individual predeterminable evaluating circuit means each having at least one signal input for the input of the signal which is to be filtered, and at least one output, each evaluating circuit means being arranged to weight the input signal thereto in accordance with an individual evaluation factor for producing at its output a weighted charge for supply to an associated input charge receiving storage position, switching element means controlling coupling of the outputs of the evaluating circuit means with the respective assigned parallel inputs for supplying the weighted charges to respective input charge receiving storage positions via the respective assigned parallel inputs, each storage position of the shift register being at least such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position, and each input charge receiving storage position being such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position and additionally able to accommodate the maximum quantity of charge supplied via its assigned parallel input, said filter being further characterized in that said shift register means comprises a first shift register (5) having first parallel inputs, and a second shift register (6) having second parallel inputs, said evaluating circuit means having first signal inputs for supply of weighted charge to the first parallel inputs of the first shift register and having second signal inputs for receiving an input signal to be filtered and for supply of weighted charge to the second parallel inputs of the second shift register, the first signal inputs of the evaluating circuit means being preceded by a time delay element (500) for delay of the signal to be filtered as supplied to the first shift register (5) in comparison to the signal to be filtered as supplied to said second shift register (6).
A transversal filter comprising analogue shift register means having successive storage positions, said shift register means having a number of parallel inputs and comprising input charge receiving storage positions having the respective parallel inputs assigned thereto, and said shift register means having a common output, a further number of individual predeterminable evaluating circuit means each having at least one signal input for the input of the signal which is to be filtered, and at least one output, each evaluating circuit means being arranged to weight the input signal thereto in accordance with an individual evaluation factor for producing at its output a weighted charge for supply to an associated input charge receiving storage position, switching element means controlling coupling of the outputs of the evaluating circuit means with the respective assigned parallel inputs for supplying the weighted charges to respective input charge receiving storage positions via the respective assigned parallel inputs, each storage position of the shift register being at least such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position, and each input charge receiving storage position being such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position and additionally able to accommodate the maximum quantity of charge supplied via its assigned parallel input, said filter being further characterized in said shift register means comprising a first shift register (5, FIG. 6) having first parallel inputs and a first series output, and a second shift register (6, FIG. 6) having second parallel inputs and a second series output connected to said common output, said first series output of said first shift register (5) being followed by a time delay means (601'), such time delay means providing a total delay time which is equal to the time required by a quantity of charge in the second shift register and in the first shift register to pass from the first-occurring to the last-occurring parallel input thereof, both said shift registers being operable with the same pulse train.
A transversal filter comprising analogue shift register means having successive storage positions, said shift register means having a number of parallel inputs and comprising input charge receiving storage positions having the respective parallel inputs assigned thereto, and said shift register means having a common output, a further number of individual predeterminable evaluating circuit means each having at least one signal input for the input of the signal which is to be filtered, and at least one output, each evaluating circuit means being arranged to weight the input signal thereto in accordance with an individual evaluation factor for producing at its output a weighted charge for supply to an associated input charge receiving storage position, switching element means controlling coupling of the outputs of the evaluating circuit means with the respective assigned parallel inputs for supplying the weighted charges to respective input charge receiving storage positions via the respective assigned parallel inputs, each storage position of the shift register being at least such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position, and each input charge receiving storage position being such that it is always able to accommodate the maximum quantity of charge supplied by a preceding storage position and additionally able to accommodate the maximum quantity of charge supplied via its assigned parallel input, said filter being further characterized in that said evaluating circuit means comprises a first group of evaluating circuits for supplying a quantity of charge which, apart from an individual evaluation factor, is equal to the difference between the relevant signal value of the signal which is to be filtered minus a predetermined minimum value which is not greater than the value of the signal minimum, and a second group of evaluating circuits for supplying a quantity of charge which, apart from an individual evaluating factor, is equal to the difference between a maximum value which is at least equal to the value of the signal maximum, minus the relevant signal value.
A process for the operation of a transversal filter as claimed in claim 22, characterized in that the analogue shift register means is operated in a known manner, that the input signal is always connected to the input of every evaluating circuit means either directly or with a time delay, that an evaluating circuit means is read-into the shift register means as a result of the closure of its switching element means at least whenever a quantity of charge is shifted from the directly adjacent storage position having a parallel input, to which at least one evaluating circuit means is connected, into the associated storage position having a parallel input, and that the filtered signal is obtained from the series output.
Dependencies are inferred from the claim text.