Harris Corporation

Matsushita Electric Industrial Co., Ltd.

Tropian, Inc.

Edwin Ray Twitchell

Robert J Plonka

Wayne Douglas Duello

Robert C Davis

Joseph Lee Seccia

Earl William McCune, Jr

Ronald A Meck

Richard W D Booth

Daniel B Talbot

Matthew Anthony Mow

Paul Henry Mizwicki

James W Hauser

The present invention, generally speaking, provides a method of obtaining very accurate estimates of the phase and amplitude distortions introduced by radio frequency or microwave power amplifiers even where polar modulation is used.

Hybrid polar modulator differential phase Cartesian feedback correction circuit for power amplifier linearization

An exciter ( ) is located along an information stream path of a transmission system ( ). The exciter ( ) supplies an information signal as a drive to an amplifying arrangement ( ). A coder ( ), programmable to be operative in any of several I/O formats, outputs the information signal that conveys data in a desired code arrangement. A filter ( ), programmable to be operative in any of several I/O formats, confines the information signal energy to a predetermined channel bandwidth. A modulator ( ), programmable to be operative in any of several I/O formats, modulating the information signal. A corrector/equalizer ( ), programmable to be operative in any of several I/O formats, pre-corrects the modulated signal for errors induced in the transmission system. A controller ( ) provides program control of the coder ( ), the filter ( ), the modulator ( ), and the corrector/equalizer ( ). Thus, the exciter ( ) is configurable to handle several formats, such as MPEG2, DVIDEO, and AES3.

Configurable exciter

An apparatus and method are provided for attenuating an undesired frequency (f ) relative to a desired frequency (f ) in a signal transmitted from an out-put ( ) of an active element ( ). Generally, the apparatus includes a parallel-resonant trap ( ) coupled to the output of the active element ( ), the trap including a network of reactive elements ( ).

Notch filter and method

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

In a digital broadcast transmission system ( ), a power amplifier ( ) amplifies an information signal to a power level suitable to excite an antenna to emit a broadcast signal. Prior to, an subsequent to, the amplification processing circuitry ( ) processes the signal. In particular, the information signal is bandpass filtered. The power amplifier ( ) causes non-linear distortion to the information signal. The processing circuitry ( ) causes linear distortions to the information signal. A single, memoryful filter ( ) pre-distorts the information signal to compensate for all of the linear and non-linear distortions. Preferably, the memoryful filter ( ) is a volterra filter. In another embodiment, a memoryful filter ( ) pre-distorts an information signal to compensate for linear distortion from a power amplifier ( ) and non-linear distortion from pre-amplification processing circuitry ( ). Linear distortion from post-amplification processing circuitry is compensated by a linear equalizer ( ). For each embodiment, the number of compensation steps is reduced compared to a sequence in which separate compensation occurs.

Broadcast transmission system with single correction filter for correcting linear and non-linear 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., ). 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

A transmission system ( ) broadcasts an information signal. Within the system ( ), several components (e.g., ) cause distortion to the information signal as the signal is processed and proceeds toward a broadcast antenna. Specifically, the group of distortion causing components ( ) is identified as a first group, and is arranged in a sequence along a signal path ( ) toward the antenna. The first group of components ( ) performs various functions, including amplification, but each subjects the information signal to distortion shifts away from intended values. A second group of components (e.g., ) modifies the information signal to compensate for the distortion shifts imposed by the first group of components ( ). The second group of components ( ) is located upstream of the first group of components ( ). The second group of components ( ) is arranged in a sequence to modify the information signal to compensate for the distortions in an order inverse to the occurrence of the distortions. Specifically, compensation for linear and non-linear distortions occurs in an order that is inverse to the occurrence of the linear and non-linear distortions.

Broadcast transmission system with distributed correction

An adaptive apparatus (,) for compensating a linear distorting action to an information signal within a non-ideal transmission system (,). Within the system (,), an information signal proceeds to a transmitter (,) that has an amplifier (,). A sample signal is coupled-off from the transmitter (,). The linear distorting action of the system (,) includes shifting of at least one aspect of the signal away from its intended value. A linear pre-equalizer (,), located along a signal stream of the information signal to the transmitter (,), pre-equalizes the information signal. An adaptive equalization determination (,), connected to receive the sample signal and the information signal outside of the signal stream to the transmitter (,), determines an amount of pre-equalization required from the linear pre-equalizer (,) to compensate the linear distorting action of the system (,). The pre-equalization by the linear pre-equalizer (,) is modified in response to the determination by the adaptive equalization determination (,).

Adaptive pre-equalization apparatus for correcting linear distortion of a non-ideal data transmission system

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.

The present invention provides an apparatus for providing error correction data in a digital data transfer system. The apparatus receives a clock signal and provides a first signal using the clock signal. Information data is received and a second signal is provided using the information data. The information data is received in groups which each have a first predetermined number of elements. A plurality of &agr;ROMs provide Galois Field multiples in look-up tables. The &agr;ROMs are addressed using the first signal to provide a first address component and using the second signal to provide a second address component. Modula mathematics are performed utilizing the values from the &agr;ROMs to generate error correction data. The error correction data is in groups each having a second predetermined number of elements. A RAM is accessible by a Trellis encoder and has an array for holding the information data elements and error correction data elements. The number of array locations is equal to an integer multiple of the sum of the first and second predetermined numbers. Further, the information and error correction data elements are sent to the RAM in third groups. A first array location always receives a first element of one of the third groups of data. Thus, the data is easily interleaved by the Trellis encoder.

Apparatus for providing error correction data in a digital data transfer system

An adaptive apparatus for compensating the non-linear distorting action of an amplifier in a transmission system. I-channel and Q-channel memories store a plurality of digital pre-distortion correction values. The memories are addressed using a predetermined number of significant bits of an incoming, original information signal to retrieve I-channel and Q-channel pre-distortion correction values. The I-channel and Q-channel pre-distortion correction values are combined, digitally, with I-channel and Q-channel components of the original information signal to pre-distort the original information signal. The pre-distorted signal, in real format, is supplied to the amplifier, and a feed-back sample signal is coupled-off of the output of the amplifier. A comparison is made between the original information signal and the feed-back sample signal in digital format and in the complex domain (I/Q). In response to the comparison, the pre-distortion correction values (I/Q) in the memory means are modified.

Adaptive pre-distortion apparatus for linearizing an amplifier output

An apparatus for compensating signal distortion via use of a feedback path, with reduced analog to digital conversion capacity requirements. In one embodiment, the apparatus is part of a transmission system which has an analog amplifier that distorts an information signal. Prior to the amplification, the information signal is provided in a digital format, processed digitally, and converted to analog for input to the amplifier. A sample signal is coupled off of output of the amplifier and applied along the feedback path. An analog-to-digital converter is located along the feedback path. A pre-distortion corrector is at the end of the feedback path. The pre-distortion corrector operates upon the source information using feedback data indicative of the amplifier distortion. Specifically, the information signal is pre-distorted (prior to input to the amplifier) to compensate for the distortion of the amplifier. A summation device is located along the feedback path, upstream of the analog-to-digital converter, to remove a source-based portion from the sample signal and for providing the sample signal containing only the amplifier distortion portion to the converter for conversion to digital.

Apparatus with reduced A/D dynamic range requirement in a compensating

A digital signal processing device and method for vestigial sideband (VSB) modulation of a digital signal. A 2.sup.n -ary digital signal d.sub.i is provided to a baseband shaping filter which samples the signal to provide a baseband signal which has real and imaginary portions Re(S.sub.bb (kT)) and Im(S.sub.bb (kT)), where ##EQU1## The VSB signal is provided with perfect sideband suppression without using analog filters. The digital signal processing device and method is characterized by requiring minimal bandwidth in the shaping filter.

Device and method for digital vestigial sideband modulation

A test signal generator presents a test signal of pseudorandom data in a format which simulates the Grand Alliance Transmission Layer Signal for the 8- or 16- vestigial sideband (8/16-VSB) signal for Advanced Television (ATV) systems. An actual (non-test) Transmission Layer 8/16-VSB signal for ATV is in a particular format with properly formatted sync information and includes data which have been randomized, Reed-Solomon coded, interleaved, and trellis coded. The test signal generator provides data in the particular 8/16-VSB format which simulates the Grand Alliance transmission signal.

Vestigial sideband test signal generator and method

Spurious frequency components from the output signal of a direct digital synthesizer are reduced with minimum degradation of the fundamental frequency of the output signal. The synthesizer has a phase accumulator for receiving digital multibit modulation data words from a source, a periodic wave function converter for converting the modulation data words into digital waveform data words and a digital-to-analog converter for converting the digital waveform data words into an analog signal which serves as the output signal. The output signal has a frequency and waveform dictated by the modulation data words. Reduction of spurious frequency components is achieved by generating a dither waveform representing a band limited waveform. The dither waveform is summed with the modulation data words prior to application to the wave function converter to provide a dither modulated analog output signal. A sampled dither signal is combined with the dither modulated analog output signal in such a manner that the dither waveform is cancelled from the fundamental waveform of the analog output signal.

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San Jose, CA, United States of America

Edwin Ray Twitchell