Calibration circuit for echo and noise cancelling of handsfree system in mobile phone

摘要

PURPOSE: A calibration device for removing a noise in a handsfree device of a mobile communication terminal is provided to store data corresponding to echo phenomenon and the peripheral environment of an internal portion of a vehicle in an EEPROM(Electrically Erasable and Programmable ROM), compare the stored data with input data sensed in a calibration unit, and remove an echo and various noises when the stored data are identical to the input data. CONSTITUTION: A DSP(Digital Signal Processor)(30) processes a voice signal of a handsfree device, stores signal data outputted from a codec(33) in an EEPROM(31) to have a calibration value, compares signal data sensed in a calibration unit(32) with the signal data stored in the EEPROM(31), and removes an echo and a noise when the signal data sensed in the calibration unit(32) are identical to the signal data stored in the EEPROM(31). The EEPROM(31) stores data corresponding to the echo and various noise values according to the peripheral environment of an internal portion of a vehicle. The calibration unit(32) senses the echo and various noises according to the peripheral environment of the internal portion of the vehicle, and outputs the sensed echo and noises to the DSP(30). The codec(33) converts transmitting and receiving audio signals into a data signal capable of being processed in the DSP(30).