scholarly journals Iterative Signal Processing for Mitigation of Analog-to-Digital Converter Clipping Distortion in Multiband OFDMA Receivers

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Markus Allén ◽  
Toni Levanen ◽  
Jaakko Marttila ◽  
Mikko Valkama

In modern wideband communication receivers, the large input-signal dynamics is a fundamental problem. Unintentional signal clipping occurs, if the receiver front-end with the analog-to-digital interface cannot respond to rapidly varying conditions. This paper discusses digital postprocessing compensation of such unintentional clipping in multiband OFDMA receivers. The proposed method iteratively mitigates the clipping distortion by exploiting the symbol decisions. The performance of the proposed method is illustrated with various computer simulations and also verified by concrete laboratory measurements with commercially available analog-to-digital hardware. It is shown that the clipping compensation algorithm implemented in a turbo decoding OFDM receiver is able to remove almost all the clipping distortion even under significant clipping in fading channel circumstances. That is to say, it is possible to nearly recover the receiver performance to the level, which would be achieved in the equivalent nonclipped situation.

2000 ◽  
Vol 46 (2) ◽  
pp. 343-352 ◽  
Author(s):  
A. Baschirotto ◽  
G. Brasca ◽  
V. Colonna ◽  
P. Cusinato ◽  
G. Gandolfi

1992 ◽  
Vol 02 (02) ◽  
pp. 325-340 ◽  
Author(s):  
ORLA FEELY ◽  
LEON O. CHUA

Oversampled sigma-delta modulators are finding widespread use in audio and other signal processing applications, due to their simple structure and robustness to circuit imperfections. Exact analyses of the system are complicated by the presence of a discontinuous nonlinear element—a one-bit quantizer. In this paper, we study the dynamics of the one-dimensional mapping which models the behavior of the single-loop modulator. This mapping has a discontinuity at the origin and constant slope at all other points. With slope one, the dynamics in the region of interest reduce to those of the rotation of the circle. With slope less than one, almost all system inputs give rise to globally asymptotically stable periodic orbits. We emphasize the case with slope greater than one, and explain the structure of the resultant bifurcation diagram. A symbolic dynamics based study allows us to explain the self-similarity of the dynamics and the nature of chaos in the system.


2021 ◽  
Vol 10 (3) ◽  
pp. 234
Author(s):  
Yuni Puji Widiastuti

ABSTRAK Air susu ibu merupakan nutrisi terbaik untuk bayi namun tidak semua ibu mampu memberikan ASI Eksklusive kepada bayinya. Pembatasan sosial selama pandemi virus corona (COVID-19) menimbulkan kekhawatiran dan stres bagi banyak orang tak terkecuali ibu menyusui. Selain itu adanya ancaman penularan virus membuat ibu merasa tidak nyaman dan stress sehingga berpengaruh terhadap kondisi kesehatan dan produksi ASI. Kurangnya pengetahuan ibu dan keluarga tentang upaya peningkatan kesehatan dan produksi ASI dimasa pandemic merupakan masalah mendasar yang dapat berpengaruh terhadap keberhasilan pemberian ASI Eksklusive yang berdampak terhadap kesehatan ibu dan bayi serta tumbuh kembang bayi disaat ini maupun dimasa mendatang. Penelitian ini bertujuan untuk mengidentifikasi tingkat pengetahuan ibu menyusui tentang upaya untuk menigkatkan kesehatan dan produksi ASI di masa pandemi. Desain penelitian ini adalah penelitian deskriptif dengan pendekatan crossectional. Samppel sebanyak 57 responden yang diambil dengan tehnik concecutive sampling. Analisis data menggunakan statistic deskriptif yang menampilkan frekwensi dan persentase. Hasil penelitian menunjukkan bahwa hamper keseluruhan responden memiliki tingkat pengetahuan baik tentang upaya untuk mneingkatkan kesehatan yaitu sebanyak 46 responden (80,7%) dan hamper keseluruhan responden memiliki tingkat pengetahuan yang baikntentang upaya meningkatkan produksi ASI yaitu sebanyak 48 responden (84,2%). Simpulan dari penelitian ini adalah tingkat pengetahuan ibu menyusui tentang upaya untuk meningkatkan kesehatan dan produksi ASI berada pada kategori Baik. Kata Kunci: Ibu menyusui, produksi ASI, tingkat pengetahuan, upaya untuk meningkatkan kesehatan, ABSTRACT Breastmilk is the best nutrition for babies but not all mothers are able to give exclusive breastfeeding to their babies. Social restrictions during the coronavirus (COVID-19) pandemic cause worry and stress for many people, including breastfeeding mothers. In addition, the threat of virus transmission makes mothers feel uncomfortable and stressed full and so that it affects health conditions and breastmilk production. Lack of knowledge of mothers and families about efforts to improve health and breastmilk production during a pandemic is a fundamental problem that can affect the success of exclusive breastfeeding which has an impact on the health of mothers and babies and the growth and development of babies now and in the future. This study aims to identify the level of knowledge of breastfeeding mothers about efforts to improve health and milk production during the pandemic. The design of this research is descriptive research with a cross-sectional approach. A sample of 57 respondents was taken using a consecutive sampling technique. Data analysis uses descriptive statistics that display the frequency and percentage. The results showed that almost all respondents had a good level of knowledge about efforts to improve health, as many as 46 respondents (80.7%) and almost all respondents had a good level of knowledge about efforts to increase breast milk production, as many as 48 respondents (84.2%). The conclusion of this study is that the level of knowledge of breastfeeding mothers about efforts to improve health and milk production is in the Good category. Keywords: Breastfeeding mothers, breastmilk production, level of knowledge, efforts to improve health 


Sign in / Sign up

Export Citation Format

Share Document