NTSC/DTV reception apparatus automatically conditioned for NTSC signal reception responsive to 4.5 MHz intercarrier

摘要

Television signal reception apparatus for receiving a television signal selected from among transmitted television signals of different types includes a respective receiver portion for each of the different types. The current reception or non-reception of NTSC signal is detected by ascertaining whether or not 4.5 MHz intercarrier sound intermediate-frequency signal is generated in the receiver portion used for NTSC signal reception. When reception of NTSC signal is detected, the television signal reception apparatus is automatically conditioned for selecting the demodulated NTSC signal for further processing.