Basic block diagram of a speech recognition system is shown in Fig.
a) In speech recognition system using microphone one can input speech or voice. The analog speech signal is converted to digital speech signal by speech digitizer. Such digital signal is called digitized speech.
b) The digitized speech is processed by DSP system. The significant features of speech such as its formats, energy, linear prediction coefficients are extracted. The template of this extracted features are compared with the standard reference templates. The closed matched template is considered as the recognized word.
c) Voice operated consumer products like TV, VCR, Radio, lights, fans and voice operated telephone dialing are examples of DSP based speech recognized devices.