Abstract
The Data Acquisition System is the integral part of the speech recognition system. The speech recognition system is used for applications such as voice dialing and speech-to-text conversion. Acquiring the human voice and storing the data is very important aspect of that system. The Data Acquisition System provides exactly the same functionality. This project report gives the background information for the analog signal sampling techniques, Analog-to-Digital converter (ADC). It discusses the AVR ATmega32A microcontroller’s internal ADC interfacing with the microphone using the pre-amplifier circuit. After the speech is sampled through the internal ADC of the Atmega32A, the project report gives the description of Serial Peripheral Interface (SPI) and a serial flash interfacing with the SPI port of the AVR. Finally, the Pulse-width Modulation is described in the final section. The PWM waveform from the AVR ATmega32A is then passed through the low-pass filter and then through the power amplifier to regenerate the original signal. The AVR STK500 is the development board used to implement the hardware. The software for the AVR microcontroller is written with C programming language. The project is successfully demonstrated using this board.