Patent ID: 7783062

Claim:
An automatic audio distortion control method for use in an automatic audio distortion control apparatus comprising an amplifier ( 6 ) and a feedback loop which has its both ends coupled to an input and an output of the amplifier ( 6 ), wherein said method has clipping distortion of signals outputted from the amplifier ( 6 ) as a control parameter for automatic control on the distortion of the amplifier ( 6 ) and comprises the steps of: a) performing sampling on levels outputted from an amplifier ( 6 ); b) converting the sampled levels into pulses representing durations of clipping distortion; c) measuring multiple pulse widths t 1 to tn within period of time ΔT; d) calculating an equivalent mean distortion D eq for the period of time ΔT with the multiple pulse widths t 1 to tn; e) comparing the calculated equivalent mean distortion D eq with a predefined distortion threshold D o ; and f) generating a gain control correction instruction for the amplifier ( 6 ) based upon the comparison result, wherein the equivalent mean distortion D eq has the following relationship with the multiple pulse widths t 1 to tn: D eq = ∑ j = 1 n ⁢ ⁢ ( tj ) m ⁢ m and m is one of 1, 2 and 3.