Ditemukan 2 dokumen yang sesuai dengan query
Randy Satria Putra
Proses transmisi sinyal dari pengirim menuju ke penerima dalam system telekomunikasi memiliki gangguan noise dan multipath fading yang disebabkan oleh reflection, scattering, atau difraction. Data rate yang tinggi pada kanal fading menyebabkan bandwidth koheren kanal menjadi lebih sempit jika dibandingkan dengan bandwidth sinyal sehingga kanal mengalami frekuensi selektif fading. Untuk mengatasinya, salah satunya adalah dengan digunakannya teknik modulasi multi carrier dengan tujuan agar sinyal mengalami flat fading pada tiap subcarrier. Teknik multi carrier yang popular digunakan adalah Orthogonal Frequency Division Multiplex (OFDM). Namun, salah satu kekurangan teknik ini adalah nilai Peak to Average Power Ratio (PAPR) yang tinggi. PAPR merupakan perbandingan daya puncak dengan daya rata-rata sinyal. Nilai PAPR yang tinggi menyebabkan penurunan performasi sistem OFDM. Skripsi ini membahas perancangan dan analisis metode reduksi PAPR dengan menggunakan transformasi wavelet dan teknik clipping agar didapatkan reduksi PAPR yang lebih baik sehingga dapat meningkatkan performansi OFDM. Dari hasil perancangan dan analisa didapatkan penurunan nilai PAPR yang signifikan, khususnya pada wavelet rbio3.7 dan teknik Deep Clipping.
ABSTRACTThe process of signal transmission from transmitter to receiver in a telecommunication system has some disturbance such as noise and multipath fading caused by reflection, scattering, or difraction. High data rate in the fading channel causes the channel coherent bandwidth becomes narrower compared to the signal bandwidth so that the channel has frequency selective fading. To overcome this problem, the multi carrier modulation technique is used with the aim to have a flat signal fading on each subcarrier. The well-known multi-carrier technique is Orthogonal Frequency Division Multiplex (OFDM). However, one of the drawbacks of this technique is the Peak to Average Power Ratio (PAPR) is high. PAPR is ratio between the peak power and the average power of the signal. High PAPR values causes degradation in system?s performance. This thesis designs and analyses PAPR reduction using wavelet transform and clipping techniques in order to obtain better PAPR reduction to improve the performance of OFDM system. The results of design and analysis show a significant reduction in PAPR value, especially when wavelet rbio3.7 and Deep Clipping techniques are used."
Fakultas Teknik Universitas Indonesia, 2012
S42614
UI - Skripsi Open Universitas Indonesia Library
"Signal quality is an important aspect in transmission system. In the real world, the signal being sent in the transmission system is random-. In this experiment, Pseudo Random Signal Generator (PRSG) has been designed and constructed which can produce random but periodic digital signal that represents the signal in the real world. Because of the signal is random, it can represents many transition possibilities, including long high, long low, leading tow to high transition, leading high to low transition, trailing low to high transition, and trailing high to low transition. All of these transitions were shown on an oscilloscope, the transition signals synchronized to the signal clock will resemble the eye pattern. Eye pattern is a simple and useful method to understand the characteristics of digital signal and its quality in the transmission system. For the purpose of achieving a good eye pattern we have to match the characteristic impedance in transmission line with the termination. The measurement showed that the quality of signal also depends on the Baud rate and the length of the transmission line."
JIUPH 4:8 (2001)
Artikel Jurnal Universitas Indonesia Library
