Distortion tolerant linear phase modulations
First Claim
1. A signal and information transmission system and a method for communications or radar overcoming the distortion that can be caused by RF circuits including any of power amplifiers or up-converters or mixers or by the channel, the system comprising:
- means for using error correcting codes to combat both the distortion caused by either RF circuits including power amplifiers and up-converters and mixers or the channel and the noise at the same time;
means for constructing phase modulated signals which can tolerate the distortion caused by the saturation of power amplifiers or the distortion caused by RF circuits such as up-converters and mixers or the channel;
means for minimizing the distortion caused by saturated power amplifiers and RF circuits to phase-shift-keyed signals at the output of one saturated power amplifier or many saturated power amplifiers or RF circuit;
means for employing any of class-C, class-D, class-E, or class-F power amplifiers, or class-A, class-B, class-AB power amplifiers working in the saturated region for signal power amplification or transmission;
means for simplifying the processes of design, development and manufacturing of power amplifiers, up-converters, mixers, RF circuits, radio terminals, communications terminals and radar;
means for reducing the radio cost, power amplifier cost, up-converter cost, mixer cost and terminal cost;
means for increasing the reliability of power amplifiers and RF circuits and the reliability of radio terminals;
means for achieving high spectral efficiency in the presence of distortion caused by power amplifiers, up-converters, mixers and RF circuits;
means for simplifying the terminal design, development and manufacturing;
means for increasing the battery life for communication terminals operated on battery;
means for filtering the received signal with distortion and noise by filters that are matched to the filters in the transmitter;
means for detecting the received signal;
means for estimating parameters in the received signal;
means for tracking the received signal in the presence of distortion and noise;
means for demodulating the received signal using the error correcting codes; and
means for achieving the bit error rate performance which is almost the same as the ideal linear BPSK bit error rate when any of class-F, class-E, class-D and class-C power amplifiers, or any of class-A, class-B, class-AB power amplifiers working in the saturated region is employed.
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Abstract
A signal and information transmission system for communications or radar and a method of achieving distortionless transmission of linear phase shift keying signals amplified by nonlinear power amplifiers or distorted by up-converters and RF circuits or the channel. Error correcting codes are used to jointly overcome both the distortion by the power amplifiers or up-converters and RF circuits or the channel and the noise. The modulator generates properly pulse shaped PSK signal, which does not have constant envelope. The signal-to-distortion power ratio is maximized to be above 20 dB at the fully saturated power amplifier output. The simplest linear receiver is provided to demodulate the received signal in the presence of radio distortion, channel distortion and noise. The decoder makes decision in the presence of radio distortion, channel distortion and noise. The method guarantees distortionless transmission of PSK signals for communications systems or radar employing power amplifiers of high DC-to-AC power conversion efficiency including class-F, class-E, class-D, class-C, or any of class-A, class-B, class-AB working in the saturation region. The method can achieve high bandwidth efficiency.
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Citations
32 Claims
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1. A signal and information transmission system and a method for communications or radar overcoming the distortion that can be caused by RF circuits including any of power amplifiers or up-converters or mixers or by the channel, the system comprising:
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means for using error correcting codes to combat both the distortion caused by either RF circuits including power amplifiers and up-converters and mixers or the channel and the noise at the same time;
means for constructing phase modulated signals which can tolerate the distortion caused by the saturation of power amplifiers or the distortion caused by RF circuits such as up-converters and mixers or the channel;
means for minimizing the distortion caused by saturated power amplifiers and RF circuits to phase-shift-keyed signals at the output of one saturated power amplifier or many saturated power amplifiers or RF circuit;
means for employing any of class-C, class-D, class-E, or class-F power amplifiers, or class-A, class-B, class-AB power amplifiers working in the saturated region for signal power amplification or transmission;
means for simplifying the processes of design, development and manufacturing of power amplifiers, up-converters, mixers, RF circuits, radio terminals, communications terminals and radar;
means for reducing the radio cost, power amplifier cost, up-converter cost, mixer cost and terminal cost;
means for increasing the reliability of power amplifiers and RF circuits and the reliability of radio terminals;
means for achieving high spectral efficiency in the presence of distortion caused by power amplifiers, up-converters, mixers and RF circuits;
means for simplifying the terminal design, development and manufacturing;
means for increasing the battery life for communication terminals operated on battery;
means for filtering the received signal with distortion and noise by filters that are matched to the filters in the transmitter;
means for detecting the received signal;
means for estimating parameters in the received signal;
means for tracking the received signal in the presence of distortion and noise;
means for demodulating the received signal using the error correcting codes; and
means for achieving the bit error rate performance which is almost the same as the ideal linear BPSK bit error rate when any of class-F, class-E, class-D and class-C power amplifiers, or any of class-A, class-B, class-AB power amplifiers working in the saturated region is employed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of minimizing the distortion caused by at least one saturated power amplifier or up-converter or RF circuit to phase modulated signals, the method comprising of the steps of:
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mapping k bits d=(d1,d2, . . . ,dk) at a time to one of M=2k phases, the mapped phase is φ
(d), which is a symbol;
feeding the coefficient cos φ
(d) to a first finite impulse response filter for summing a series of the delayed filter coefficients {p(j)} weighted by the symbol coefficients {cos φ
(d)} to form the filtered in-phase signal; and
feeding the coefficient sin φ
(d) to a second finite impulse response filter for summing a series of the delayed filter coefficients {p(j)} weighted by the symbol coefficients {sin φ
(d)} to form the filtered quadrature signal. - View Dependent Claims (23, 24, 25)
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26. A method of achieving high spectral efficiency through proper pulse shaping in the presence of distortion caused by RF circuits including any of saturated power amplifier or up-converter or mixer or RF circuit for communications systems or radar employing phase shift keying.
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27. A linear demodulator to demodulate the received signal in the presence of both distortion and noise, the linear demodulator comprising:
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a first down-converter to convert the received signal in the in-phase channel to baseband;
a second down-converter to convert the received signal in the quadrature channel to baseband;
a sampling circuit to sample the baseband signals in both the in-phase channel and the quadrature channel;
an analog-to-digital converter to convert the sampled baseband signals to digital signals;
a first finite impulse response filter matched to the shaping filter for the in-phase channel in the transmitter, the filter performs low-pass filtering for the samples in the in-phase channel;
a second finite impulse response filter matched to the shaping filter for the quadrature channel in the transmitter, the filter performs low-pass filtering for the samples in the quadrature channel;
a signal detector to detect the incoming signal using the matched filter output;
a parameter estimator to estimate the symbol timing, carrier frequency offset and carrier phase using the matched filter output;
a tracking loop to track the carrier frequency, carrier phase and the symbol timing; and
a decoder to make decisions on the received symbols using the tracking loop output.
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28. A method of simplifying the design, development, manufacturing and testing of power amplifiers, up-converters, mixers, RF circuits, radio terminals and communications terminals for communications systems or radar employing phase shift keying.
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29. A method of increasing the reliability of power amplifiers, RF circuits, radio terminals and communications terminals for communications systems or radar employing phase shift keying.
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30. A method of reducing the power amplifier cost, up-converter cost, radio cost and terminal cost for communications systems or radar employing phase shift keying.
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31. A method of increasing the battery life for communications terminals operated on battery.
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32. A method of reducing the power consumption in transmitters for communications systems or radar employing phase shift keying.
Specification