Harris Corporation

Google Inc.

Gatesair, Inc.

Anders S Mattsson

Christopher Douglas Moffatt

Carlos G Abascal

Wayne Douglas Duello

John W Pajunen

Ky Thoai Luu

Kevin Berndsen

Sean R Rogers

David Danielssons

Systems and methods are provided for broadcasting a for broadcasting a modulated signal. A plurality of peaks is detected within a waveform envelope signal of the modulated signal. For each of the plurality of peaks, a pulse having substantial spectral content that is outside of a passband of a high power filter is constructed. The constructed pulse for each peak is subtracted from its associated peak to provide a peak-reduced signal. The peak-reduced signal is amplified at a power amplifier to provide an amplified signal. The amplified signal is filtered at the high power filter to provide a filtered signal. The filtered signal is broadcast at an associated antenna.

Peak-to-average reduction with post-amplifier filter

An apparatus and method measures power of channels generated by a multiple-carrier transmitter that upconverts a plurality of baseband signals to a corresponding plurality of assigned carrier frequencies to generate an RF wideband signal. A measurement module's input interface receives a selected baseband signal and a corresponding assigned carrier frequency as well as the RF wideband signal. An undersampling component undersamples the RF wideband signal for a sampling interval to generate a plurality of measured aliased samples. A determination component determines a plurality of determined aliased samples based on the selected baseband signal upconverted to the corresponding assigned carrier frequency. A correlator correlates the plurality of measured aliased samples with the plurality of determined aliased samples to produce a correlation result. A transmit power component determines a transmitted power of the correlation result for a selected channel of the RF wideband signal corresponding to the selected baseband signal as upconverted.

Power detection of individual carriers of a multiple-carrier wideband signal

A system communicates data and includes a transmitter for transmitting a communications signal that carries communications data. It includes an efficient modulator for approximating the frequencies of sine/cosine basis waveforms using complex exponential functions and adding and subtracting the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data as data symbols. A receiver receives the OFDM communications signal and includes a demodulation circuit for demodulating the OFDM communications signal using logical shifts of multiples +/&#x2212;2based on complex exponential functions corresponding to sine/cosine basis waveform approximations to extract amplitude and phase values from a plurality of N data subcarriers as data symbols within the OFDM communications signal.

System and method for communicating data using efficient fast fourier transform (FFT) for orthogonal frequency division multiplexing (OFDM)

A communications device includes a signal input that receives an orthogonal frequency division multiplexed (OFDM) communications signal. A demodulator is connected to the signal input for receiving the OFDM communications signal and demodulating the OFDM communication signal. It includes at least one memory element for storing the at least one sine/cosine basis waveform approximation as complex exponential functions. A logic circuit performs logical shifts in additions and multiples of +/&#x2212;2and extracts amplitude and phase values from a plurality of N data subcarriers within the OFDM communications signal. The demodulator includes efficient implementation of the FFT for use as an OFDM demodulator where the complex exponentials are approximated by multi-level complex sinusoids and optionally oversampled to increase SNR of the FFT output.

System and method for communicating data using efficient fast fourier transform (FFT) for orthogonal frequency division multiplexing (OFDM) demodulation

A communications device includes at least one memory device for storing complex exponential functions as approximations of sine and cosine basis waveforms. A logic circuit adds and subtracts the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data. The logic circuit provides efficient and accurate implementation of the IFFT for use as an OFDM modulator using additions of stored complex exponentials and modulation of the integer-valued QAM data symbols using logic shifts and sign changes (2's complement).

System and method for communicating data using efficient fast fourier transform (FFT) for orthogonal frequency division multiplexing (OFDM) modulation

Systems and methods are provided for precorrecting a constant envelope input signal. A phase precorrection component generates a precorrected input signal by applying a phase precorrection to the input signal. The applied phase correction alters an associated phase of the input signal without applying amplitude modulation to the signal. A linear distortion source applies amplitude distortion and phase distortion to the precorrected input signal. The applied phase correction mitigates the phase distortion applied by the linear distortion source.

Phase correction of a constant envelope signal without introducing amplitude modulation

Systems and methods are provided for synchronizing a plurality of transmitters in a distributed transmission system. A data source generates a digital signal. A central data processing component inserts synchronization data into the digital signal. The synchronization data includes a periodic reset signal. A plurality of radio frequency transmitters each comprises a Trellis coder. At least one Trellis coder state at each Trellis coder is reinitialized to a predefined default state in response to the reset signal.

Transmitter synchronization in a distributed transmission system

A circuit for use in a broadcast transmitter for adaptively compensating for carrier signal distortions caused by amplitude modulating an RF carrier signal. The circuit includes a modulator/amplifier network that receives an RF carrier signal and modulates it by a received amplitude varying signal to obtain therefrom a modulated carrier signal which may exhibit distortions caused by the amplitude modulating of the RF carrier signal. A digitally adaptive corrector precorrects the amplitude varying signal prior to application thereof to the network to compensate for any modulated carrier signal distortions. This includes a digital processor that provides signal correction as a function of digital samples representing amplitude variations of the modulated RF carrier signal.

Digitally adaptive modulated transmitter

A method and apparatus are disclosed for predistorting an input signal to a non-linear amplifier. An appropriate precorrection is determined for the input signal over a series of iterative stages according to an amplifier model. The amplifier model includes a limiting function that clips the input signal to reduce error due to amplifier saturation. The determined precorrection is then applied to the input signal.

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Mason, OH, United States of America

Anders S Mattsson