| 摘要 |
PURPOSE:To stabilize an automatic gain controlling system composed of an amplitude discriminating section, pattern discriminating section, AGC amplifier, etc., by bringing the output signal level nearer to a reference value only when an input signal is the same as or similar to a training pattern. CONSTITUTION:An adder circuit 5, inter-code interference quantity discriminating circuit 8, equalizing pulse generating circuit 9, and adder circuit input terminal 6 and output terminal 7 constitute a decision feedback type transversal equalizer. Signals outputted to the output terminal 7 are added to an amplitude discriminating section 10 and pattern discriminating section 15 and the output signal of each section 10 and 15 is supplied to the two input terminals 12 and 13 of a gain control discriminating section 11. The discriminating section 11 discriminates that the output signal of the amplitude discriminating section 10 is effective when the signal of the input terminal 13 is '1' and supplies the gain controlling signal of an AGC amplifier to a terminal 3 from the output terminal of the discriminating section 11. Therefore, only when the signal inputted in an input terminal 1 is the same as or similar to a training pattern, it is discriminated that whether the scale of the amplitude of the signal is larger than a reference value or not and the output signal level is controlled so as to bring the level close to the reference value. |
