| 摘要 |
PURPOSE:To reduce high frequency distortion by raising an FM demodulation output to the (n)th power and then differentiating it, and mixing the differentiation output and (n)-power output. CONSTITUTION:An FM receiver supplies the output of an FM demodulator 3 to a trailing stage through a distortion canceling circuit 4. The distortion canceling circuit 4 consists of an adder 11 supplied with the FM demodulation output, a squaring circuit 16 and a cubing circuit 17, differentiating circuits 18 and 20 which differentiate the outputs of the squaring circuit 16 and cubing circuit 17 respectively, differentiating circuits 19 and 21 which differentiate the outputs of the differentiating circuts 18 and 20 respectively, level adjusting circuits 22, 23, 24, and 25 which adjust the output levels of the differentiating circuits 18, 19, 20, and 21 respectively, and adders 12, 13, and 14. Then, the input/output level ratio of each level adjusting circuit is adjusted properly to cancel the 2nd and the 3rd higher harmonic distortions of the FM demodulation output. |
