Informatics Publishing Limited

Mousumi Mondal , Kanika Trivedy , S. Nirmal Kumar , Vineet Kumar , Srinivas V. Bandlamori

Abstract

The cocoon filaments and degummed fibers of CSR2 x CSR4 (Bivoltine hybrid) and PM x CSR2 (Multivoltine x Bivoltine hybrid) of Bombyx mori were examined under a scanning electron microscope (SEM). The degummed fibers obtained from the different methods used earlier, were under taken to study the characteristics of degummed fibers. The morphological study revealed that the diameter of the cocoon filament was 15 μm in diameter in PM x CSR2 hybrid and 12 μm in CSR2 x CSR4 hybrid, when studied at ultra structural level. In all the degummed process, the diameter of the degummed fiber of both the hybrids were 6 µm except soap soda degumming method, where the diameter of degummed fiber was measured 6.3 μm and the difference was due to the soap attachment to the degummed fiber. The degummed fibers were noticed intact in soap soda and 1% Na₂CO₃ methods.  However, in Gulrajani method, the fibers were noticed fibrillation of 1.2 µm diameter which may be due to the more time taken for degumming process.

Full Text

   

S. Nirmal Kumar ¹, B. K. Santhosh ¹

Affiliations
1 Department of Electronics & Communication Engineering, Jaya Engineering College, Prakash Nagar, Chennai-602024, IN

Abstract

The demand for high-speed mobile wireless communications is rapidly growing. OFDM technology promises to be a key technique for achieving the high data capacity and spectral efficiency requirements for wireless communication systems of the near future. Fast Fourier transform (FFT) processing is one of the key procedures in popular orthogonal frequency division multiplexing (OFDM) communication systems. Structured pipeline architectures, low power consumption, high speed and reduced chip area are the main concerns in this VLSI implementation. In this paper, the efficient implementation of FFT processor for OFDM applications is presented. This processor can be used in various OFDM-based communication systems, such as Worldwide Interoperability for Microwave access (Wi-Max), digital audio broadcasting (DAB), digital video broadcasting-terrestrial (DVB-T). The three processing elements (PE’s), delay-line (DL) buffers are used for computing FFT. Thus we consume low power, low hardware cost high efficiency and reduced chip size.

Keywords

FFT, PE, Twiddle Factor, OFDM, Modified Booth Multiplier, SDF, Radix-2&4.

Full Text