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Continuous phase modulation

About: Continuous phase modulation is a research topic. Over the lifetime, 3199 publications have been published within this topic receiving 37245 citations. The topic is also known as: CPM.


Papers
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Journal ArticleDOI
TL;DR: Morphine as discussed by the authors uses modern gradient descent techniques to extract optical aberrations given only the intensity distribution on the sensor, which can be used for post-processing of existing data, or for the design of optical phase masks optimized to achieve high contrast, angular resolution, or astrometric stability.
Abstract: The principal limitation in many areas of astronomy, especially for directly imaging exoplanets, arises from instability in the point spread function (PSF) delivered by the telescope and instrument. To understand the transfer function, it is often necessary to infer a set of optical aberrations given only the intensity distribution on the sensor—the problem of phase retrieval. This can be important for post-processing of existing data, or for the design of optical phase masks to engineer PSFs optimized to achieve high-contrast, angular resolution, or astrometric stability. By exploiting newly efficient and flexible technology for automatic differentiation, which in recent years has undergone rapid development driven by machine learning, we can perform both phase retrieval and design in a way that is systematic, user-friendly, fast, and effective. By using modern gradient descent techniques, this converges efficiently and is easily extended to incorporate constraints and regularization. We illustrate the wide-ranging potential for this approach using our new package, Morphine. Challenging applications performed with this code include precise phase retrieval for both discrete and continuous phase distributions, even where information has been censored such as heavily saturated sensor data. We also show that the same algorithms can optimize continuous or binary phase masks that are competitive with existing best solutions for two example problems: an apodizing phase plate coronagraph for exoplanet direct imaging, and a diffractive pupil for narrow-angle astrometry. The Morphine source code and examples are available open-source, with an interface similar to the popular physical optics package Poppy.

8 citations

Proceedings ArticleDOI
23 Apr 2004
TL;DR: CPM is an efficient waveform for future satellite communication systems that yields good power and spectral performance and provides a constant envelope signal so that SSPA (solid state power amplifier) terminal amplifier can operate near saturation.
Abstract: In this paper, a CPM (continuous phase modulation) based waveform is proposed. CPM is an efficient waveform for future satellite communication systems. It yields good power and spectral performance and provides a constant envelope signal. This class of modulation yields a constant envelope signal so that SSPA (solid state power amplifier) terminal amplifier can operate near saturation. These systems operate in Ka-band with MF-TDMA access method on the uplink with the requirements of future satellite communication systems. The system will overcome specific difficulties that may affect the quality of service. The brief summary of the main CPM signal properties and the receiver complexity, serially coded CPM with iterative decoding process is presented. Simulation results are presented in the paper such that coding and decoding schemes achieve good power performance.

8 citations

Journal ArticleDOI
TL;DR: The authors present an efficient software-aided technique for phase error reduction in CR for high-order QAM, based on the simple and well-known fourth power CR loop, which allows a significant improvement of bandwidth efficiency by increasing the modulation order, at the cost of slight complexity overhead.
Abstract: With increasing order of quadrature amplitude modulation (QAM), the bandwidth efficiency is improved in digital communication. However, in practice, the modulation order is limited, since conventional digital carrier recovery (CR) algorithms give rise to unacceptable phase error. The authors present an efficient software-aided technique for phase error reduction in CR for high-order QAM, based on the simple and well-known fourth power CR loop. Analytical and simulation results indicate that the new technique has several attractive features such as approximate of invariance of phase error improvement over modulation order and low hardware complexity for modulation orders as high as 256-QAM. Experimental results for 64 and 256-QAM illustrate phase error variance of less than −110 dBc/Hz at the frequency offset of 10 kHz, that is, 30 dB reduction of phase error variance or 3 dB increase in system processing gain compared to the conventional fourth power CR loop. This allows a significant improvement of bandwidth efficiency by increasing the modulation order, at the cost of slight complexity overhead.

8 citations

Journal ArticleDOI
TL;DR: The optimal linear modulation approximation of any M-ary continuous-phase modulated (CPM) signal under the minimum mean-square error (MMSE) criterion is presented in this paper.
Abstract: The optimal linear modulation approximation of any M-ary continuous-phase modulated (CPM) signal under the minimum mean-square error (MMSE) criterion is presented in this paper. With the introduction of the MMSE signal component, an M-ary CPM signal is exactly represented as the superposition of a finite number of MMSE incremental pulses, resulting in the novel switched linear modulation CPM signal models. Then, the MMSE incremental pulse is further decomposed into a finite number of MMSE pulse-amplitude modulated (PAM) pulses, so that an M-ary CPM signal is alternatively expressed as the superposition of a finite number of MMSE PAM components, similar to the Laurent representation. Advantageously, these MMSE PAM components are mutually independent for any modulation index. The optimal CPM signal approximation using lower order MMSE incremental pulses, or alternatively, using a small number of MMSE PAM pulses, is also made possible, since the approximation error is minimized in the MMSE sense. Finally, examples of the MMSE-optimal CPM signal approximation and its comparison with the Laurent approximation approach are given using raised-cosine frequency-pulse CPM schemes.

8 citations

Proceedings ArticleDOI
01 Jan 2017
TL;DR: A carrier recovery for a 300 GHz system based on the parallel transmission of a reference frequency together with the payload data is proposed and the corresponding electronic circuits for the transmitter and receiver are designed, manufactured and characterized.
Abstract: The carrier frequencies of wireless systems are expanded to higher and higher frequency bands where huge bandwidths for data-hungry applications can be realized. One of the prospective regions is the sub-millimeterwave band. Wireless transmission needs coherent local oscillators at the transmitter and receiver for efficient operation. At such high frequencies, traditional methods of analog carrier recovery (e.g. narrowband filtering of the residual carrier and re-amplification) fail. At the same time, for high data rates above 10 Gbit/s, digital carrier recovery algorithms used in conjunction with free-running oscillators are too power-hungry and hard to realize. In this paper, a carrier recovery for a 300 GHz system based on the parallel transmission of a reference frequency together with the payload data is proposed. The corresponding electronic circuits for the transmitter and receiver are designed, manufactured and characterized.

8 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202316
202241
202136
202060
201976
201870