David Rea Schaefer

US Patent:

40527050, Oct 4, 1977

Filed:

Feb 13, 1976

Appl. No.:

5/657996

Inventors:

David H. Schaefer - Silver Spring MD
James P. Strong - Upper Marlboro MD

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

G11C 1304
G11C 1142

US Classification:

340173LM

Abstract:

Memory device for two-dimensional radiant energy array computers in which the memory device stores digital information in an input array of radiant energy digital signals that are characterized by ordered rows and columns. The memory device includes a radiant energy logic storing device having a pair of input surface locations for receiving a pair of separate radiant energy digital signal arrays and an output surface location adapted to transmit a radiant energy digital signal array and a regenerative feedback device that couples one of the input surface locations to the output surface location in a manner for causing regenerative feedback.

US Patent:

39964558, Dec 7, 1976

Filed:

May 8, 1974

Appl. No.:

5/468614

Inventors:

David H. Schaefer - Silver Spring MD
James P. Strong - Upper Marlboro MD

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

H03K 1914

US Classification:

235152

Abstract:

Two-dimensional digital computers and computer devices operate in parallel on rectangular arrays of digital radiant energy optical signal elements which are arranged in ordered rows and columns. Logic gate devices receive two input arrays and provide an output array having digital states dependent only on the digital states of the signal elements of the two input arrays at corresponding row and column positions. The logic devices include an array of photoconductors responsive to at least one of the input arrays for either selectively accelerating electrons to a phosphor output surface, applying potentials to an electroluminescent output layer, exciting an array of discrete radiant energy sources, or exciting a liquid crystal to influence crystal transparency or reflectivity. An image combiner/duplicator serves as an interface device for either converting two spaced apart input arrays to a combined input array or for converting an input array to two spaced apart output arrays. Interconnecting devices provide an output array having signal element digital states dependent on the states of non-corresponding input signal elements.

US Patent:

40457923, Aug 30, 1977

Filed:

Feb 13, 1976

Appl. No.:

5/657997

Inventors:

David H. Schaefer - Silver Spring MD
James P. Strong - Upper Marlboro MD

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

H03K 1302

US Classification:

340347AD

Abstract:

Analog to digital converter for two-dimensional radiant energy array computers in which the converter stage derives a bit array of digital radiant energy signals representative of the amplitudes of an input radiant energy analog signal array and derives an output radiant energy analog signal array to serve as an input to succeeding stages. The converter stage includes a digital radiant energy array device which contains radiant energy array positions so that the analog array is less than a predetermined threshold level and which doesn't contain radiant energy at array positions where the input analog array exceeds the threshold level. A scaling device amplifies the radiant energy signal levels of the input array and the digital array so that the radiant energy signal level carried by the digital array corresponds to the threshold level. An adder device adds the signals of the scaled input and digital arrays at corresponding array positions to form the output analog array.