CROSSTALK ELIMINATING DEVICE FOR SECAM COLOR SIGNAL OF MAGNETIC RECORDER AND REPRODUCER

摘要

PURPOSE:To simplify the constitution of a modulator circuit, by securing a constant free-running frequency for an FM demodulator circuit and then varying the clamping voltage of a modulated signal with every H in case an FM-modulated SECAMFM signal is extracted after eliminating the crosstalk. CONSTITUTION:The SECAM reproduced color signal is applied to the crosstalk eliminating circuit 22 from the terminal 21, and the main and secondary line sequential color difference signals are produced at the 1st and 2nd demodulator circuits 23 and 25 of the circuit 22. Then the secondary signal is substrated from the main signal through the 1st and 2nd difference circuits 26 and 28 to eliminate the crosstalk. The color signal with the crosstalk eliminated is supplied to the FM demodulator circuit 30 via the clamping circuit 29 and then converted into the SECAM color signal through the circuit 30. Then the SECAMFM signal is extracted through the terminal 31. An alternating modulation is given to the circuit 30 with every reference subcarrier of R-Y and B-Y to secure a constant free-running frequency. Thus the constitution is simplified for the modulator circuit that extracts the FM signal.