| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiplex audio demodulator in a television, which can suppress excessive discrimination switching without increasing the circuit scale. SOLUTION: The multiple audio demodulator is provided with a pulse counter 2 that discriminates the frequency of a discrimination signal, a variable current source 3 controlled by the pulse counter 2, a time constant capacitor 4 and a load resistor 5 connected to the variable current source 3, a reference constant voltage source 6 connected in series with the load resistor 5, a 1st comparator 9 that is connected to a 2-audio discrimination constant voltage source 7, and a 2nd comparator 10 connected to a stereo discrimination constant voltage source 8. The 1st (2nd) comparator 9 (10) compares an output voltage on the basis of an output of the variable current source 3 with a set voltage of the 2-audio discrimination constant voltage source 7 (stereo discrimination constant voltage source 8) to provide an output of a reception state signal.
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