Method and apparatus for multiplexed oversampled analog to digital modulation

Claim 2

Apparatus responsive to an array of m analog inputs for producing a bit stream output representative thereof, said apparatus comprising: m storage elements, each capable of storing an analog value; N bit A/D converter means, responsive to an applied analog value, for producing a bit stream output representative thereof; multiplexing means for periodically applying a residue analog value from each of said m storage elements to said A/D converter means, each residue analog value associated with a different one of said m analog inputs; N bit D/A converter means, responsive to said A/D converter means bit stream output, for producing quantized values each coarsely representative of a residue analog value applied to said A/D converter means; means for summing each of said m analog inputs and its associated residue analog value and differencing the quantized value associated therewith to form a new residue analog value; and demultiplexing means for storing each new residue analog value in one of said m storage elements.

Claim 3

Apparatus of claim 1 wherein said N bit A/D converter means comprises a single bit A/D converter and said N bit D/A converter means comprises a single bit D/A converter.

Claim 4

Apparatus of claim 1 wherein said m storage elements each comprise a charge control device well.

Claim 5

An imager responsive to an energy pattern incident on a focal plane for producing a bit stream representative thereof, said imager comprising: an array of energy sensitive elements disposed on said focal plane for producing m analog signals; M storage elements, each capable of storing an analog value; N bit A/D converter means, responsive to an applied analog value, for producing a bit stream output representative thereof; multiplexing means for periodically applying a residue analog value from each of said m storage elements to said A/D converter means, each residue analog value associated with a different one of said m analog signals; N bit D/A converter means, responsive to said A/D converter means bit stream output, for producing quantized values each coarsely representative of a residue analog value applied to said A/D converter means; means for summing each of said m analog signals and its associated residue analog value and differencing the quantized value associated therewith to form a new residue analog value; and demultiplexing means for storing each new residue analog value in one of said m storage elements.

Claim 6

An imager responsive to an energy pattern incident on a focal plane for producing a bit stream representative thereof, said imager comprising: an array of energy sensitive elements disposed on said focal plane for producing m analog signals; M storage elements, each capable of storing an analog value; N bit A/D converter means, responsive to an applied analog value, for producing a bit stream output representative thereof; multiplexing means for periodically applying a residue analog value from each of said m storage elements to said A/D converter means, each residue analog value associated with a different one of said m analog signals; N bit D/A converter means, responsive to said A/D converter means bit stream output, for producing quantized values each coarsely representative of a residue analog value applied to said A/D converter means; means for summing each of said m analog signals and its associated residue analog value and differencing the quantized value associated therewith to form a new residue analog value; and demultiplexing means for storing each new residue analog value in one of said m storage elements.

Claim 7

The imager of claim 4 wherein said energy sensitive elements comprise light sensitive elements for each generating a charge potential related to the energy of light focused thereon.

Claim 8

The imager of claim 4 wherein said array of energy sensitive elements comprises an orthogonal array of charge control devices.

Claim 9

The imager of claim 4 wherein said N bit A/D converter means comprises a single bit A/D converter and said N bit D/A converter means comprises a single bit D/A converter.

Claim 10

An imager responsive to an energy pattern incident on a focal plane for producing an output bit stream representative of said pattern, said imager comprising: an array of m energy collection elements, each capable of producing an analog signal related to the amount of energy incident thereon; means mounting each of said m energy collection elements for collecting energy from a different area of said focal plane; means for storing m analog residues, each associated with a different one of said collection elements; A/D converter means sequentially responsive to said m analog residues for producing an output stream comprised of bits, each related to one of said analog residues; D/A converter means responsive to said output stream bits for respectively producing analog quantized estimates, each related to one of said analog residues; and processing means for periodically modifying the stored value of each analog residue as a function of the analog signal produced by the associated collection element and the analog quantized estimate produced by said D/A converter means.

Claim 11

An imager responsive to an energy pattern incident on a focal plane for producing an output bit stream representative of said pattern, said imager comprising: an array of m energy collection elements, each capable of producing an analog signal related to the amount of energy incident thereon; means mounting each of said m energy collection elements for collecting energy from a different area of said focal plane; means for storing m analog residues, each associated with a different one of said collection elements; A/D converter means sequentially responsive to said m analog residues for producing an output stream comprised of bits, each related to one of said analog residues; D/A converter means responsive to said output stream bits for respectively producing analog quantized estimates, each related to one of said analog residues; and processing means for periodically modifying the stored value of each analog residue as a function of the analog signal produced by the associated collection element and the analog quantized estimate produced by said D/A converter means.

Claim 12

The apparatus of claim 8 wherein said processing means includes means sequentially summing each presently stored analog residue with the analog signal produced by the associated collection element and differencing that quantity with the associated quantized estimate for modifying the presently stored analog residue to produce a new analog residue.

Claim 13

The apparatus of claim 9 wherein said means for storing m analog residues comprises; m serially connected storage elements including an input storage element and an output storage element; and means for shifting said analog residues through said m serially connected storage elements from said input to said output storage element.

Claim 14

The apparatus of claim 10 wherein said processing means derives each presently stored analog residue from said output storage element and delivers each new analog residue to said input storage element.

Claim 15

The apparatus of claim 10 wherein each of said m storage elements is mounted proximate to a different one of said m collection elements; and further comprising means for periodically transferring the analog signal produced by each collection element to the storage element mounted proximate thereto.

Claim 16

The apparatus of claim 8 wherein said m energy collection elements comprise light sensitive elements arranged in a two-dimensional array substantially coincident with said focal plane.

Claim 17

The apparatus of claim 10 including: an array of m transfer elements, each coupled to a different one of said m collection elements; means for periodically transferring the analog signal produced by each collection element to the transfer coupled thereto; said m transfer elements being serially arranged and including an output transfer element; means for shifting said analog residues through said m serially connected transfer elements to said output transfer element; and wherein said processing means sequentially derives said analog signals from said output transfer element.

Claim 24

The method of claim 17 wherein said disposing step comprises the steps of: mounting on said focal plane an array of light sensitive elements; and generating, with each of said elements, a charge potential related to the energy of light focused thereon.