NTSC INTERFERENCE ELIMINATION METHOD USING 3-STAGE NOTCH FILTER AND NTSC INTERFERENCE ELIMINATION FILTER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To selectively eliminate the frequency component that causes an interference between the NTSC channels among those signals which are received via a 3-stage notch filter without accompanying unnecessary loss of a desired digital signal by comparing the 1st energy with the 2nd energy to produce a selection signal that controls an output path and then controlling this path. SOLUTION: A minimum energy detector 400 is connected to the 1st and 2nd integrators 230 and 330 and compares the energy value of the 1st and 2nd energy calculation parts 200 and 300 with each other to supply a prescribed selection control signal 301 to an output part 500. The part 500 uses the received I channel data symbol 103 and the output of a 1st 3-stage notch filter 120 as its input signals. Then the output signal of the detector 400 is used as the signal 301 to selectively output one of both input signals 103 and 102 that is fitted with the relevant condition.