JPS5582570A - Audio multiplex receiver - Google Patents

Abstract

PURPOSE:To increase the accuracy of discrimination with small size and cheap cost and to increase the reliability, by discriminating whether or not multiplex broadcast with the magnitude of control signal through the provision of the signal selection means and enabling the identification of dual broadcast or stereo broadcast. CONSTITUTION:The detection output of the terminal 23 passes through BPF 24 and the maximum output obtained at the peak hold circuit 25 is converted into binary level at the threshold value circuit 26. When control signal is present, H level signal is outputted to the terminal 27 and when absent, L level signal is fed to the terminal 27. Thus, the presence of multiplex broadcast can be discriminated. On the other hand, the output of BPF24 is detected at the AM detection circuit 28 and inputted to the signal selection means 29. The output of the means 29 is different from the magnitude on input frequency, and the magnitude of the output is converted into binary level with the peak hold circuit 30 and the threshold value circuit 31. One of the control signals different in two frequency is taken as H level and another is as L level to be outputted at the output terminal 32. Thus, dual broadcast or stereo broadcast can be identified.