Low noise charge coupled device transversal filter

A charge coupled transversal filter for providing a desired impulse response having a first and second polarity comprising

• a substrate,
• a plurality of split weighting electrodes positioned along said substrate adjacent to each other, each split electrode having an insulating gap between first and second portions thereof, said gaps having a configuration of said impulse response with the split electrodes representative of the first polarity response having an inverted configuration and the electrodes representative of the second polarity having a noninverted configuration,
• a source of reference potential coupled to the first portions of said split electrodes,
• first and second output leads respectively coupled to the second portions of said inverted and noninverted split electrodes, and
• combining means coupled to said first and second output leads for inverting the signal received from said split electrodes having the inverted configuration.

A charge coupled transversal filter for providing a selected impulse response having first and second polarity portions, said impulse response being defined by a plurality of weighting coefficients of first and second polarities, comprising

• a substrate,
• a plurality of weighting electrodes positioned adjacent to each other and along said substrate, each weighting electrode having first and second portions split with an insulating gap, each of said second portions having a length proportional to one of said weighting coefficients, said electrodes corresponding to coefficients of a second polarity having gaps forming an inverted configuration of said impulse response,
• reference means coupled to the first portions of said split electrodes,
• first and second leads coupled to the second portions representing respective first and second polarity weighting coefficients, for respectively forming the first and second polarity portions of said impulse response, and
• combining means coupled to said first and second leads for inverting the signal on said second lead.

A CCD transversal filter having a selected impulse response formable from a plurality of first and second polarity weighting coefficients comprising

• a substrate,
• a plurality of split weighting electrodes positioned on said substrate for each providing a first plurality weighting coefficient of the selected impulse response, each split electrode having first and second ends,
• a source of a reference potential coupled to the first ends of said split electrodes,
• a first output lead coupled to the second ends of the weighting electrodes corresponding to the first polarity weighting coefficients of said impulse response,
• a second output lead coupled to the second ends of the weighting electrodes corresponding to the second polarity weighting coefficients of said impulse response,
• and combining means coupled to the first and second output leads for inverting the signal in said second lead and combining with the signals on said first output lead.

A CCD transversal filter operable to develop a selected impulse response from a plurality of predetermined weighting coefficients being of both first and second polarities comprising

• a plurality of split weighting electrodes each having a portion with an upper width and a portion with a lower width, said lower width of each weighting electrode defining a weighting coefficient of a first polarity,
• a group of transfer electrodes positioned adjacent to each split electrode,
• clock means coupled to each group of transfer electrodes for transferring charges between said split electrodes,
• reference means coupled to the portion of said split weighting electrodes with an upper width,
• first and second output leads respectively coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said first polarity and coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said second polarity, and
• combining means having inverting and noninverting inputs respectively coupled to said first and second output leads.

A CCD transversal filter to provide a selected impulse response to input charges and defined by a plurality of time sequential weighting coefficients being both positive and negative comprising

• a substrate,
• a plurality of split electrodes positioned along said substrate and having first and second portions, said second portions each having a surface area representative of a weighting coefficient, said second portions of said plurality of split electrodes having surface areas selected along said substrate to provide said time sequential weighting coefficients,
• a source of reference potential coupled to the first portions of said split electrodes,
• first and second output conductors respectively coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the first polarity and coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the second polarity, and
• combining means having an inverting and a noninverting input terminal respectively coupled to said first and second output conductors.

A CCD transversal filter having a characteristic to provide a selected impulse response defined by a plurality of weighting coefficients comprising:

• a substrate having first and second ends,
• a plurality of split weighting electrodes positioned along said substrate between said first and second ends, said split weighting electrodes each having a gap between first and second portions to provide one of said weighting coefficients as a function of the length of said second portion,
• a reference potential coupled to the first portion of each of said split weighting electrodes,
• signal combining means coupled to the second portion of each of said split weighting electrodes, and
• sample and hold means including first and second pentodes coupled between the second portions of said split weighting electrodes and said means for coupling all of said second portions.

A CCD transversal filter comprising:

• a substrate having first and second ends;
• a plurality of weighting electrodes positioned along said substrate between the first and second ends, each of said weighting electrodes split into first and second portions, said weighting electrodes having the split configuration to provide a selected filter characteristic;
• a constant voltage bias source coupled to a first portion of each of said split electrodes;
• a plurality of output leads selectively coupled to the second portion of each of said split electrodes;
• and
• combining means coupled to said plurality of output leads.