Harris Corporation

Wayne Douglas Duello

Ky Thoai Luu

Edwin Ray Twitchell

Robert J Plonka

Anders S Mattsson

Carlos G Abascal

Douglas J Posey

George Cabrera

Timothy Wilfred Dittmer

Theodore H Korte

David Danielssons

Scott Frederick Halozan

A digital exciter is presented herein for use in RF broadcasting and wherein the exciter employs pilot signal compensation. This includes an input digital circuit for receiving a modulated digital data at an input sample rate for RF broadcasting at a desired RF frequency. The pilot frequency may be displaced from a desired location at the frequency band because of an error in the input sample rate. A digital compensator determines whether the pilot frequency is displaced and provides a digital correction signal in accordance therewith. A digital correction circuit corrects the pilot frequency in accordance with the correction signal.

Digital exciter having pilot signal compensation

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 pulse width modulator is presented herein and it includes a pulse width driver circuit that receives a time varying ramp signal that is modulated by a time varying analog input signal to produce a pulse width modulated drive signal comprised of turn-on pulses having widths that vary with variations in the magnitude of said input signal. A switch is turned on by each drive pulse for a time duration dependent upon the duration of each drive pulse and provides an output signal therefrom. A negative bias amplifier provides a negative bias signal that has pulsations that are synchronized with said drive pulses but of opposite phase. A combiner combines output signal with the negative bias signal to provide a combined output signal.

Pulse width modulator circuit having negative bias

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.

Precorrection of a nonlinear amplifier

A transmission system ( ) broadcasts a signal. Within the system ( ), a power amplifier ( ) causes non-linear distortion. A pre-amp component, such as a band-pass filter ( ), causes linear distortion. A high power filter ( ) is located downstream of the power amplifier ( ) and causes linear distortion. A linear equalizer ( ) compensates for the distortion caused by the high power filter ( ). A non-linear corrector ( ) compensates for the distortion caused by the power amplifier ( ), and is located downstream of the linear equalizer ( ). A linear equalizer ( ) compensates for the distortion caused by the pre-amp components (e.g., ). The compensating components ( ) are located upstream of the distorting, pre-amp component (e.g., ). Signal sampling points ( ) are located downstream of each distorting component ( , and ). Sampling selectively occurs at one of the sample points ( ) for use to update compensation.

Broadcast transmission system with sampling and correction arrangement for correcting distortion caused by amplifying and signal conditioning components

A transmission system ( ) broadcasts a signal. Within the system ( ), a power amplifier ( ) causes non-linear distortion. A pre-amp component, such as a band-pass filter ( ), causes linear distortion. A high power filter ( ) is located downstream of the power amplifier ( ) and causes linear distortion. A linear equalizer ( ) compensates for the distortion caused by the high power filter ( ). A non-linear corrector ( ) compensates for the distortion caused by the power amplifier ( ), and is located downstream of the linear equalizer ( ). A linear equalizer ( ) compensates for the distortion caused by the pre-amp components (e.g., ). The compensating components ( ) are located upstream of the distorting, pre-amp component (e.g., ). A interpolation component ( ) is located between the three compensating components ( ) and the distortion causing components ( , and ) to increase a rate of the signal, such that the compensation occurs at a lower rate of the signal. Signal sampling points ( ) are located downstream of each distorting component ( , and ). Sampling selectively occurs at one of the sample points ( ) for use to update compensation.

Broadcast transmission system with correction for distortion caused by amplifying and signal conditioning components at a different rate

Apparatus and method are presented for adaptively compensating for carrier signal phase distortion caused by amplitude modulating an RF carrier signal. A modulator-amplifier network receives an RF carrier signal and modulates it by a received amplitude varying signal to obtain therefrom a modulated RF carrier signal which is phase shifted from the phase of the carrier signal applied to the network by an amount that varies with the value of the amplitude varying signal. A phase shifter receives the RF carrier signal and phase shifts it in accordance with the value of a received phase correction signal to provide a pre-phase shifted carrier signal that is applied to the modulator-amplifier network. A phase detector receives and compares the modulated RF carrier signal and the carrier signal and provides an error signal in accordance with the comparison. An adaptive controller provides the correction signal and receives the error signal and the amplitude varying signal and varies the value of the correction signal in accordance with the value of the error signal and the value of the amplitude varying signal.

Adaptive compensation for carrier signal phase distortion

A transmission system (,) broadcasts a signal. Within the system (,), a power amplifier (,) causes non-linear distortion. A pre-amp component, such as a band-pass filter (,), causes linear distortion. A high power filter (,) is located downstream of the power amplifier (,) and causes linear distortion. A linear equalizer (,) compensates for the distortion caused by the high power filter (,). A non-linear corrector (,) compensates for the distortion caused by the power amplifier (,), and is located downstream of the linear equalizer (,). A linear equalizer (,) compensates for the distortion caused by the pre-amp components (e.g.,,). The compensating components (,) are located upstream of the distorting, pre-amp component (e.g.,,). Signal sampling points (,) are located downstream of each distorting component (,, and,). Sampling selectively occurs at one of the sample points (,) for use to update compensation.

An RF power amplifier system is presented herein. It includes a plurality of RF power amplifier modules. At least two encoders are provided. Each encoder is associated with and controls the operation of some of the plurality of power amplifier modules. Each encoder is associated with different ones of the plurality of amplifier modules. An exciter receives an amplitude varying input signal and periodically provides a command signal to each of the modulation encoders and instructs that modulation encoder as to how many of its associated power amplifier modules are to be turned on as a function of the value of the input signal. Each modulation encoder responds to a received command signal and selects which of its associated power amplifiers to turn on.

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Hamilton, OH, United States of America

Wayne Douglas Duello