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In this paper, we present the first results of spectral and timing propertiesof the atoll source 4U 1705-44 using $\sim$ 100 ks data obtained with LargeArea X-ray Proportional Counter (LAXPC) onboard {\it AstroSat}. The source wasin the high-soft state during our observations and traced out a {\it bananatrack} in the Hardness Intensity Diagram (HID). We study {\bf the} evolution ofthe Power Density Spectra (PDS) and the energy spectra along the HID. PDS showpresence of a broad Lorentzian feature (Peaked Noise or PN) centered at $1-13$Hz and a very low frequency noise (VLFN). The energy spectra can be describedby sum of a thermal Comptonized component, a power-law and a broad iron line.The hard tail seen in the energy spectra is variable and contribute $4-30$\% ofthe total flux. The iron line seen in this source is broad (FWHM $\sim$ 2 keV)and strong (EW $\sim$ $369-512$ eV). Only relativistic smearing in theaccretion disc can not explain the origin of this feature and requires othermechanism such as broadening by Comptonization process in the external part ofthe `Comptonized Corona'. A subtle and systematic evolution of the spectralparameters (optical depth, electron temperature etc.) is seen as the sourcemoves along the HID. We study the correlation between frequency of the PN andthe spectral parameters. PN frequency seems to be correlated with the strengthof the corona. We discuss the implication of the results in the paper.

Spectral and Timing Properties of Atoll Source 4U 1705-44 : LAXPC/AstroSat Results