Electronic filter e.g. non-coherent filter, for e.g. hands-free mobile phone in vehicle, has control section limiting calibration gain such that variation threshold of calibration gain does not exceed preset variation threshold

摘要

The filter e.g. non-coherent filter (26), has a noise reference for receiving a noise reference signal (42) from a vibration sensor. An estimation section (44) estimates a calibration gain relative to square of a transfer function between the sensor and a microphone. Spectral gain function is derived from the reference signal and the calibration gain for applying the gain function to an input signal of the microphone. A control section limits the calibration gain such that a variation threshold of the calibration gain does not exceed a preset variation threshold. Independent claims are also included for the following: (1) an electronic signal receiving and processing system comprising an electronic filter and a microphone (2) an electronic filtering method for processing an input signal for reducing surrounding noise.