Television signal converter

A television signal converter for selecting a television signal of an arbitrary channel out of television input signals from a plurality of channels and for converting the selected television signal of said arbitrary channel into a television output signal of a predetermined channel, each of said television input signals having a video carrier and an audio carrier, said video carrier being subjected to amplitude modulation by a video signal, to be scrambled by compressing horizontal synchronizing signal portions of said amplitude modulated video carrier by a prescribed level, while said audio carrier is subjected to frequency modulation by an audio signal and is subjected to amplitude modulation by a descrambling signal required for descrambling said scrambled video carrier, both said scrambled video carrier and said amplitude modulated audio carrier being frequency-multiplexed with each other to be transmitted as at least one of said television input signals, said television signal converter comprising:

• selecting means for selecting said television signal of said arbitrary channel out of said television input signals of said plurality of channels;
• converting means for converting said television signal of said arbitrary channel selected by said selecting means to said television signal of said predetermined channel;
• descrambling means for descrambling said predetermined channel television signal outputted from said converting means by expanding horizontal synchronizing signal portions of said predetermined channel television signal by a prescribed level;
• filter means operably connected to an output of said descrambling means for passing only said predetermined channel television signal;
• audio carrier extracting means for extracting said television signal before being descrambled by said descrambling means and for extracting said audio carrier, having been subjected to frequency modulation by said audio signal and having been subjected to amplitude modulation, from said television signal before being descrambled;
• FM demodulation means for FM demodulating said audio carrier extracted by said audio carrier extracting means in order to reproduce said audio signal;
• descrambling signal detecting means for AM detecting said audio carrier extracted by said audio carrier extracting means in order to detect said descrambling signal;
• and
• control means for controlling said descrambling means in response to said descrambling signal detected by said descrambling signal detecting means, to thereby avoid unnecessarily subjecting said audio carrier to phase modulation when said scrambled television signal with said compressed horizontal synchronizing signal portion is descrambled by said descrambling means by expanding said horizontal synchronizing signal portion.