AUTOMATIC EQUALIZING SYSTEM FOR DATA MODULATOR-DEMODULATOR

• Main Author: AOTANI YOSHIHISA
• Format: Patent
• Language: English
• Published: 18.09.1990
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

PURPOSE:To attain sufficient equalization even in the case of deficient equalization or over-equalization of an output of a fixed equalizer with a few tap number by varying the center of a tap of an automatic equalizer in response to the selection of the equalizing characteristic of the fixed equalizer. CONSTITUTION:A reception signal 1 subject to amplitude distortion and delay distortion on a line enters a fixed equalizer 101, in which the signal is equalized depending on an equalizing characteristic selection signal 2. Then the reception signal is demodulated by a demodulator 102 and given to an automatic equalizer 103. On the other hand, the signal 2 is inputted to a discriminator 104, and when the signal 2 selects a characteristic with a large gradient of the equalizing characteristic, that is, the output of the equalizer 104 represents over- equalization, an error signal 4 is outputted to the equalizer 103 so that the center of the tap of the equalizer 103 is placed to a position increasing the ratio of the pre-cursor. Moreover, when the reception signal receiving distortion on the line is not equalized by the equalizer 101, the discriminator 104 outputs a signal 4 to set the center position of the tap of the equalizer 103 so that the rate of the post-cursor is increased conversely.