High dimensionality carrierless amplitude phase modulation technique for radio over fiber system

Advanced modulation formats such as carrierless amplitude phase (CAP) modulation technique is one of the solutions to increase flexibility and high bit rates to support multi-level and multi-dimensional modulations with the absence of sinusoidal carrier. Recent work are focussing on the 2D CAP-64 QAM Radio-over-Fiber (RoF) system but no extension of higher dimensions is reported. This thesis expands the area of CAP modulation technique and RoF system. The work described in this thesis is devoted to the investigation of 1.25 GSa/s sampling rate for multi-level and multi-dimensional CAP in point-to-point (P2P) and RoF system at 3 km single-mode fiber (SMF). Another advanced modulation format which is known as discrete multitone (DMT) is compared with CAP modulation in order to observe the performance in different modulation schemes. The 4QAM-DMT and 16QAM-DMT at different number of subcarriers are carried out in this propagation. Based on the results, the transmission performance in terms of BER and received optical power for RoF transmission are degraded to almost 3 dB when comparing to 3 km SMF transmission. These are caused by the wireless power loss and impairment effects. The bit rate and spectral efficiency can be increased with the increasing number of levels, and may decreased once the number of dimensions is increased due to the higher up-sampling factor. However, the additional dimensions can be used to support multiple service applications. Therefore, it can be concluded that CAP has better performance as compared to DMT in terms of higher spectral efficiency and data rate. To conclude, the results presented in this thesis exhibit high feasibility of CAP modulation in the increasing number of dimensions and levels. Thus, CAP has the potential to be utilized in multiple service allocations for different number of users

Penanda pengemukaan topik dalam wacana pedagogi: satu analisis wacana kritis

Kebanyakan kajian lepas wacana pedagogi mengenai kemahiran mengajar guru tidak membincangkan praktis sosial wacana berdasarkan pendekatan Analisis Wacana Kritis (AWK). Kajian ini bertujuan menjelaskan praktis sosial wacana pedagogi melalui huraian penanda pengemukaan topik dalam interaksi guru-murid semasa aktiviti pengajaran mikro dan interpretasi amalan wacananya. Penanda pengemukaan topik merangkumi perkataan penanda paraton sebagai penanda wacana dan ayat tanya guru sebagai bahagian kawalan topik dalam dimensi tekstual wacana pedagogi. Kajian ini menggunakan kaedah rakaman dan transkripsi data. Data diambil melalui video rakaman selama 30 minit setiap sesi pengajaran dan pembelajaran (PdP) semasa aktiviti pengajaran mikro melibatkan 5 pelajar bakal guru di sebuah universiti awam di Jakarta dan murid sebenar dari 5 sekolah menengah di Jakarta. Kajian ini mengaplikasi AWK Fairclough (2013). Fokus analisis pada perkataan penanda paraton dan jenis ayat tanya guru. Hasil kajian ini mendapati guru menggunakan 146 perkataan penanda paraton ‘nah’, ‘ya’, ‘baik/baiklah’, ‘silakan’, ‘sekarang’, ‘lalu’, ‘anak-anak/anak-anakku’, ‘Assalamualaikum/selamat pagi/sore’, ‘selanjutnya’, ‘coba’, ‘yang pertama/kedua/ketiga’, ‘Alhamdulillah’, ‘bagaimana’, ‘wah’, ‘jadi’, ‘ayo’, ‘kalian’, ‘ohya nak’, dan ‘tolong’ pada awal gerakan sebagai cara pengemukaan topik baharu. Manakala terdapat 125 soalan guru menjadi gerakan sebagai penanda topik dan selepas perkataan penanda paraton diujarkan. Jenis ayat tanya guru berupa ayat tanya terbuka-tertutup; ayat tanya informatif-konfirmatif. Disimpulkan, kajian ini mengandungi praktis sosial kesetaraan dominasi guru-murid di bilik darjah. Guru menganggap murid sebagai subjek yang mempunyai hak untuk dihormati melalui pemilihan perkataan penanda paraton yang menunjukkan kesantunan, seperti ‘silakan’, ‘tolong’, ‘coba’, partikel ‘–kah’, serta perakuan positif terhadap respons murid. Perkara ini bertentangan dengan praktis sosiobudaya pedagogi di Indonesia bahawa kuasa sering dimiliki oleh guru. Selain itu, guru dalam kajian ini masih merupakan bakal guru sehingga murid menganggap mempunyai hubungan rapat dengan gurunya. Kajian ini menyumbang kepada kualiti PdP apabila pelajar menjadi guru serta memberi input linguistik dalam kajian wacana pedagogi dengan pendekatan AWK

Comparison of Cap and QAM-DMT Modulation Format for In-Home Network Environment

Carrierless amplitude phase (CAP) modulation format has appeared as a potential advanced modulation format candidate for spectrally efficient single-carrier modulation type due to less complexity and has competitive performance. In this paper, the comparison between 2D-CAP-4 and 4-QAM-DMT modulation format over 3 km single mode fiber (SMF) transmission link using 1310 nm vertical cavity surface emitting laser (VCSEL) has been performed for inhome network environment. The net bit rates of 625 Mb/s and 454.6 Mb/s are achieved for 2D-CAP-4 and 4-QAM-DMT, respectively. Spectral efficiencies of 1.89 b/s/Hz for 2D-CAP-4 and 1.43 b/s/Hz for 4-QAM-DMT are reported. It is observed that 2D-CAP-4 outperforms 4-QAM-DMT with 1.14 dB better receiver sensitivity. These results indicate that the privilege properties of CAP modulation format can be an attractive prospect for in-home network environment