Telcordia Technologies, Inc.

Bell Communications Research, Inc.

Vencore Labs, Inc.

University of Central Florida Research Foundation Inc

Applied Communications Sciences

Thomas C Banwell

Ted Kirk Woodward

Paul Toliver

Janet L Jackel

Ronald Charles Menendez

Stefano Galli

Anjali Agarwal

Joseph Charles Liberti, Jr

Shahab Etemad

John C Koshy

Nim K Cheung

Peter J Delfyett

Thomas J Robe

William Anderson

Keku M Mistry

James L Dixon

David L Waring

Thomas J Banwell

James E Hodge

William E Stephens

Ariel Dori

Provided are apparatus including a signal processing circuit. The signal processing circuit may be configured to process an input signal having an input bandwidth spanning a range of input radio frequencies, and may include a local oscillator to produce a local oscillator signal. In one embodiment, the signal processing circuit can include a staring mode of operation. In one embodiment, the signal processing circuit can include a selective mode of operation. In one embodiment, the signal processing circuit can include a staring mode of operation and a selective mode of operation.

Signal processing circuit with optical local oscillator signal

A high rate radio frequency (RF) link system and method for spatially multiplexing data transmission is presented. The system can comprise a common communications point characterized by a first collection of antennas having independent channels interconnected with a known latency connection to a central process location, such as with optical fiber; and a second similarly configured collective endpoint or set of endpoints wherein multi-path between the first collection and the second collection is negligible. Signal decorrelation between independent channels is achieved through a combination of spatial separation and signal processing. In one aspect, decorrelation is performed using near-maximum likelihood Multiple-Input Multiple-Output signal processing.

High rate RF link technology utilizing near-maximum likelihood MIMO signal processing

A directional notch filter for simultaneous transmit and receive of wideband signals comprises an antenna, an antenna match, a receiver, a power combiner, a first directional coupler, a second directional coupler and a shaping filter accepting a signal and producing a compensation signal as a replica of an antenna reflection transfer function, wherein the first and second directional couplers produce signals and portions of signals received by the antenna and sent to the receiver via the power combiner. The receiver can produce a receiver signal and the first directional coupler can produce a first signal as a portion of an overall signal received by the antenna, the first signal comprising at least reflection of a signal from the power amplifier and the second directional coupler samples a small portion of the receiver signal, said second directional coupler producing a second signal.

Directional notch filter for simultaneous transmit and receive of wideband signals

Apparatus and methods of simultaneous transmission and reception in a single-antenna radio transceiver. The transceiver may be used, for instance, for communication between at least two terminals, by use of multiple intermediate recruited transceiver nodes. The recruited transceiver nodes receive a signal from a master mode, and then retransmit the signal to a receiver. The recruited transceiver nodes are designed to have reduced interference between the transmit channel and the received channel. In accordance with one aspect of the present application, embodiments can achieve more robust wireless communication between a transmitter and an over-the-horizon receiver. The robust wireless communication will have improved resistance to interference, including self-interference, and improved communication range.

Directional filter for separating closely spaced channels in an HF transceiver

A system and method for optimizing an optical RF photonic link system is presented. The system comprises a modulator subsystem in which nonlinear response is compensated by an envelope precompensation method and employs an optical filter to suppress optical carriers and extract modulated sidebands, an optical amplifier, and an array of photodetectors, each having a plurality of pairs of diodes. The modulator subsystem performs optical filtering on the signal, the signal is amplified by the optical amplifier and sent to the array of photodetectors. The optical amplifier can be an erbium doped fiber amplifier, or a phase sensitive amplifier. The optical power can be delivered to each diode of the array of photodetectors via a photonic integrated circuit.

Method and apparatus for optimized analog RF optical links

A system and method for transporting encrypted data having a transmitter and a receiver is provided. The transmitter generates a sequence of optical pulses, which are copied and output as identical channels. The identical channels are modulated by a plurality of modulators using data to generate a modulated data signal. Respective spectral phase encoders coupled to each of the plurality of data modulators encode respective modulated data signals using a plurality of mutually orthogonal phase codes that are individually associated with the respective spectral phase encoder. These encoded data signals are combined and code-scrambling by a spectral phase scrambler using a scramble code as an encryption key to generate an encrypted signal. A receiver reverses the encryption to extract the data.

System and method for OCDMA-based photonic layer security robustness to archival attack

Systems and methods for improved photonically-assisted RF filtering. Presently, processing of wide-band RF signals involves the use of multiple specialized equipment to isolate a region of interest from the spectrum. The present invention discloses the use of a modulation system to upconvert the RF signal onto the sideband of a light source such as a laser, an optical filter sub-system comprising a plurality of filtering units that function as combinations of IIR and FIR filters, and a resonant channelizing filter for noise reduction and rejection of undesired channels, and means for control and agility of a piecewise coherent optical filter. The resulting filtered RF signal may then be downconverted to the electrical domain for further signal processing.

Systems and methods for photonically assisted RF filtering

A method for multiscale sampling for wide dynamic range electro-optic receivers is presented. The method comprises obtaining a signal, reproducing the signal into first and second signals, scaling one signal with respect to the other, modulating both signals with the same modulation function, and utilizing the resulting vector response function to invert the response of the link over a greater dynamic range than would otherwise be possible with a single instance of the modulated signal. The sealed modulation response may be obtained by splitting the signal into two polarizations and utilizing a modulator having different response for the two polarizations, or by utilizing two modulators.

Multiscale sampling for wide dynamic range electro-optic receivers

Apparatus and system for transmitting and receiving optical code division multiple access data over an optical network. The apparatus comprises a spectral phase decoder for decoding the encoded optical signal to produce a decoded signal, a time gate for temporally extracting a user signal from the decoded signal, and a demodulator that is operable to extract user data from the user signal. The system preferably comprises a source for generating a sequence of optical pulses, each optical pulse comprising a plurality of spectral lines uniformly spaced in frequency so as to define a frequency bin, a data modulator associated with a subscriber and operable to modulate the sequence of pulses using subscriber data to produce a modulated data signals and a Hadamard encoder associated with the data modulator and operable to spectrally encode the modulated data signal to produce an encoded data signal.

Phase chip frequency-bins optical code division multiple access

A system for performing broadband differential time domain measurement on a subscriber loop. The system comprises a waveform generator coupled to a sampling head. The sampling head includes positive and negative pulse generators each coupled to one of the lines of the subscriber loop. The subscriber lines are in turn also coupled to two inputs of a differential amplifier, whose output is connected to an oscilloscope or other detector.

System and circuitry for measuring echoes on subscriber loops

A method and system for restricting telephone access to a predetermined set of telephone numbers. The method includes comparing the output of a caller ID signal decoder to telephone numbers stored in memory and allowing the telephone call to be completed if there is match between the calling party's number and a number stored in memory. The system consists of connection circuitry to which is connected a caller ID decoder, a number comparator, and an off hook detector. These components interact to restricts calls to only those stored in the number comparator.

Method, apparatus, and system for filtering incoming telephone calls

Methods and apparatuses are provided for determining characteristics of an input optical signal in an optical network. An optical signal monitoring apparatus estimates a minimum time interval between transitions in the input signal, determines a clock signal based on the estimated minimum time interval, and performs a time domain measurement on the input signal based on the determined clock signal. The optical signal monitoring apparatus samples the input signal based on the determined clock signal and determines the characteristics of the input signal.

Method and apparatus for automated time domain monitoring in optical networks

Methods and apparatuses consistent with the present invention recover a clock signal from a variable bit rate data signal by estimating, in the time domain, the bit rate of the data signal, and based on the estimated variable bit rate, determining a center frequency of a narrow-band filter for extracting the clock signal from the data signal. A clock recovery circuit consistent with the present invention extracts a clock signal from a variable bit rate data signal by estimating a minimum time interval between transitions in the data signal, generating a plurality of pulses that correspond respectively to transitions in the data signal, adjusting the duration of each of the pulses based on the estimated minimum time interval and inputting into a narrow-band filter the adjusted pulses, determining a center frequency of the narrow-band filter based on the estimated minimum time interval, and extracting in the narrow-band filter the clock signal from the adjusted pulses.

Method and apparatus for variable bit rate clock recovery

A relatively simple voltage regulator comprises a bandgap reference, an error amplifier and a multi-function current mirror. By utilizing only NPN transistors, a high-performance arrangement characterized by good line regulation is achieved.

All-NPN-transistor voltage regulator

The laser driver circuit of the invention stabilizes the low operating output power level of a laser (301) modulated by a digital input signal, at a fixed preset value L.sub.o, by automatically adjusting the bias current, I.sub.b, supplied to the laser to compensate for variations in the laser threshold due to temperature changes and aging. The circuit includes a fast photodetector (401) which is responsive to the modulated light output of the laser. The photodetector output is combined (306, 308) with a data sensitive reference signal (i.sub.r) and a preset level setting input signal (i.sub.o) which is equal to .eta. times the desired low operating output power level L.sub.o, where .eta. is the coupling coefficient of the photodetector. Reference signal i.sub.r varies in accordance with the input data between a zero value when the input is ZERO and a value equal to what is estimated to be the photodetector output due to the data modulation when the input is ONE. The combination of the photodetector output, the data sensitive reference signal i.sub.r, and the level setting input signal i.sub.o, is a difference signal proportional by a factor of .eta. to the difference between the desired low operating output level and the estimated operating output level. This difference signal is amplified by an operational transconductance amplifier (402) having a large multiplicand, A.sub.o, when the input data is ZERO and a substantially smaller multiplicand, A.sub.1, when the input data is ONE. The output of the amplifier drives an integrating low frequency error amplifier 309 which generates at its output the laser bias current, I.sub.b, which is driven to a value such that the low operating power level of the laser is equal to L.sub.o as determined by the level setting input signal i.sub.o.

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Madison, NJ, United States of America

Thomas C Banwell