Alan C Oppenheim DeceasedFort Pierce, FL

6441764, Aug 27, 2002

May 5, 2000

09/565102

Richard Barron - Cambridge MA
Alan V. Oppenheim - Lexington MA

Massachusetts Institute of Technology - Cambridge MA

H03M 112

341155, 375141, 37524011

An apparatus and method for subband signal coding, using algorithms of comparable complexity to conventional coders, that exploits a noisy analog signal at the decoder. It is assumed that the analog signal is the output of a channel through which the source is sent uncoded. By using the analog signal at the receiver, the required digital bit rate is able to be reduced while offering comparable fidelity to conventional coding systems that ignore the analog signal. Concepts from conventional subband coding, e. g. , subband decomposition, quantization, bit allocation, and lossless bitstream coding, are tailored to exploit the analog signal at the receiver such that frequency-weighted mean-squared error (MSE) is minimized. Because subband coefficients are coded, all results pertaining to perceptual masking are easily applied to this method of coding. The invention is directed to a signal coding solution for a hybrid channel that is the composition of two channels: a noisy analog channel through which a signal source is sent unprocessed and a secondary rate-constrained digital channel.

7020286, Mar 28, 2006

Feb 15, 2002

10/077542

Wade P. Torres - Providence RI, US
Alan V. Oppenheim - Lexington MA, US
Rodolfo R. Rosales - Boston MA, US

Massachusetts Institute of Technology - Cambridge MA

H04N 7/167
H04L 9/00

380238, 380236, 713200, 713201

A system for modulating and demodulating signals that provides a new class of signal modulators and their corresponding demodulators. The modulation scheme embeds in an information signal a carrier signal by modulating the oscillatory rate of the carrier signal. The invention generalizes the possible carrier signals to any signal which can be generated by a dynamical system that have a known exponentially convergent observer, as in certain chaotic systems.

7636403, Dec 22, 2009

Jun 25, 2001

09/888762

Yonina C. Eldar - Cambridge MA, US
Alan V. Oppenheim - Lexington MA, US

Massachusetts Institute of Technology - Cambridge MA

H04L 27/06

375343

A receiver for and method of processing received signals comprising a linear combination of a plurality of signature signals having undergone some distortion. The receiver is comprised of a bank of correlators for receiving the signals, and a correlation shaper operating on a vector output from the bank of correlators. The bank of correlators may comprise a matched filter receiver or a decorrelator receiver. Optionally, a bank of detectors may operate on the vector output of the correlation shaper.

7751469, Jul 6, 2010

Feb 20, 2001

09/788890

Yonina C. Eldar - Cambridge MA, US
Alan V. Oppenheim - Lexington MA, US

Massachusetts Institute of Technology - Cambridge MA

H04B 1/707

375152

The present invention is directed toward an apparatus and method for receiving signals, demodulating the signals and shaping the correlation of the output of a correlation demodulator. The present invention can be used irrespective of whether the received signals have noise components that are Gaussian or non-Gaussian. Moreover, the present invention can be utilized when a predetermined set of received signals is linearly independent or linearly dependent.

5208786, May 4, 1993

Aug 28, 1991

7/750917

Ehud Weinstein - Ramat-gam, IL
Meir Feder - Herzliya, IL
Alan V. Oppenheim - Lexington MA

Massachusetts Institute of Technology - Cambridge MA

G01S 1500

367124

A system separates unknown signals which have been combined together through unknown linear filters and for which observations at multiple sensors are made. In a two channel circuit with two inputs and two sensors, the reconstructed source signals are assumed to be decorrelated such that the cross-correlation between the reconstructed source signals is near zero. The transfer functions which represent the crosstalk processes are estimated. The output signals are detected and the transfer functions are recursively solved. A reconstruction filter is used to recover the original input signals.

5285478, Feb 8, 1994

Oct 31, 1991

7/786003

Gregory W. Wornell - Brookline MA
Alan V. Oppenheim - Lexington MA

Massachusetts Institute of Technology - Cambridge MA

H04L 2700

375 37

A communication system is provided in which a transmitter performs modulation upon a number sequence to be transmitted. The modulation scheme includes embedding a sequence of numbers into a waveform such that the sequence is present in the waveform on multiple time scales. The transmitted waveform has a selected number of different frequency bands of successively doubling bandwidths. Each of the frequency bands includes the sequence of numbers, repeated therein at a certain rate. The rate is directly proportional to the bandwidth of the frequency band. The communication system further includes a receiver designed to average the value of the repeated sequence as received by the receiver. This scheme allows for accurate communication over noisy, uncertain, and/or hostile channels in both point to point and broadcast communication applications.

5293425, Mar 8, 1994

Dec 3, 1991

7/802121

Alan V. Oppenheim - Lexington MA
Ehud Weinstein - Rumat-Gan, IL
Kambiz C. Zangi - Cambridge MA
Meir Feder - Herzilia, IL

Massachusetts Institute of Technology - Cambridge MA

G10K 1116

381 71

A noise reducing system includes an input transducer that energizes an adaptive filter. The adaptive filter energizes an output transducer that creates a noise reducing field at the input transducer.

5291555, Mar 1, 1994

Dec 14, 1992

7/989703

Kevin M. Cuomo - Chelmsford MA
Alan V. Oppenheim - Lexington MA

Massachusetts Institute of Technology - Cambridge MA

H04K 102
H04L 928

380 6

A chaotic transmitter (100) operates according to preselected chaotic protocols, such as a set of Lorenz equations. Modulation is accomplished by modifying a predetermined parameter of the set of chaotic Lorenz equations with a message signal, thereby producing a spread spectrum chaotic transmitted signal. A corresponding receiver (200) reconstructs a synchronizing drive signal, which is used by a demodulator (412) of the receiver (200) to detect the message signal.