In this paper, a robust DWPT based adaptive bock algorithm with modified threshold for denoising the sounds of musical instruments shehnai, dafli and flute is proposed. The signal is first segmented into multiple blocks depending upon the minimum mean square criteria in each block, and then thresholding methods are used for each block. All the blocks obtained after denoising the individual block are concatenated to get the final denoised signal. The discrete wavelet packet transform provides more coefficients than the conventional discrete wavelet transform (DWT), representing additional subtle detail of the signal but decision of optimal decomposition level is very important. When the sound signal corrupted with additive white Gaussian noise is passed through this algorithm, the obtained peak signal to noise ratio (PSNR) depends upon the level of decomposition along with shape of the wavelet. Hence, the optimal wavelet and level of decomposition may be different for each signal. The obtained denoised signal with this algorithm is close to the original signal.

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We presents an on-chip tunable wide ranged multiple output CMOS voltage reference based on non-volatile highly precise field programmable floating gate transistors. The reference is outfit for both sub 1V and above 1V applications. The circuit design consists of basic beta multiplier configuration and offers a strategy of making the current sourcing circuit and reference generating circuit as independent units. A simulation model of the circuit was built in T-Spice, 0.35µm CMOS process. Simulation results show high amount of temperature insensitivity for a large range of thermal conditions. The reference voltage variation is about 1.65mV/°C to 1.67mV/°C over wide temperature range of -40 to 140°C; has an impressive static supply dependency of 125µV/V for a reference of 280mV. The circuit can also be operated at very low supply voltage (0.5v).

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