High security pay television system

Claim 2

A television receiver adapted for use in a pay television system in which broadcast signals are scrambled comprising turner means for receiving the broadcast signal and for separating the broadcast signal into at least two components; a decoder circuit connected to receive a first one of the components from the tuner means; a mixer to combine the output of the decoder circuit with the first component of the output of the tuner means; a television screen and associated driver circuitry to display the output of the mixer; an electrically alterable memory module containing a first memory portion in which at least one pre-written external code is carried and a second memory portion in which program information may be entered; a microprocessor in the decoder circuit programmed to (1) read the external code from the memory module, (2) derive a broadcast code from the video signal, (3) generate a descrambling signal from the external code and output the descrambling signal to the mixer, and (4) to write information about programs actually being descrambled, as determined by the broadcast code, in the memory module so that use of the receiver to view scrambled broadcasts can be billed on a usage basis; and means for descrambling a second of the separated components of the broadcast signal from the tuner means separately from the other components so that full, descrambled composite video signal is not available at any one point in the receiver.

Claim 3

A television receiver as claimed in claim 1 wherein the tuner means includes a synch separator to separate a synch signal from the components video signal, wherein the separated synch signal is the second component, and wherein the descrambling means descrambles that synch signal independently of the composite video.

Claim 4

A television receiver adapted for use in a pay television system in which broadcast signals are scrambled comprising a tuner to receive the broadcast signal and derive a video signal therefrom; a decoder circuit connected to receive the video signal from the tuner, a mixer to combine the output of the decoder circuit with a first component of the output of the tuner; a television screen and associated driver circuitry to display the output of the mixer; an electrically alterable memory module containing a first memory portion in which at least one pre-written external code is carried and a second memory portion in which program information may be entered; and a microprocessor in the decoder circuit programmed to (1) read the external code from the memory module, (2) derive a broadcast code from the video signal, (3) recognize in the broadcast code whether the program signal is being received over the air or from a video cassette tape, (4) generate a descrambling signal from the external code, the descrambling signal being different depending on the source of the signal, and output the descrambling signal to the mixer, and (4) to write information about programs actually being descrambled, as determined by the broadcast code, in the memory module so that use of the receiver to view scrambled broadcasts can be billed on a usage basis and so that the receiver can descramble programming recorded on video cassette in partially descrambled format.

Claim 5

A television receiver adapted for use in a pay television system in which broadcast signals are scrambled comprising a tuner to receive the broadcast signal and derive a video signal therefrom; a decoder circuit connected to receive the video signal from the tuner, a mixer to combine the output of the decoder circuit with a first component of the output of the tuner; a television screen and associated driver circuitry to display the output of the mixer; an electrically alterable memory module containing a first memory portion in which at least one pre-written external code is carried and a second memory portion in which program information may be entered; and a microprocessor in the decoder circuit programmed to (1) read the external code from the memory module, (2) derive a broadcast code from the video signal, (3) recognize in the broadcast code whether the program signal is being received over the air or from a video cassette tape, (4) generate a descrambling signal from the external code, the descrambling signal being different depending on the source of the signal, and output the descrambling signal to the mixer, and (4) to write information about programs actually being descrambled, as determined by the broadcast code, in the memory module so that use of the receiver to view scrambled broadcasts can be billed on a usage basis and so that the receiver can descramble programming recorded on video cassette in partially descrambled format.

Claim 6

A television receiver adapted for use in a pay television system in which broadcast signals are scrambled comprising a tuner to receive the broadcast signal and derive a video signal therefrom; a decoder circuit connected to receive the video signal from the tuner; a mixer to combine the output of the decoder circuit with a component of the output of the tuner; a television screen and associated driver circuitry to display the output of the mixer; an electrically alterable memory module containing a first memory portion in which at least one pre-written external code is carried; and a microprocessor in the decoder circuit programmed to (1) read the external code from the memory module, (2) derive a broadcast code from the video signal, (3) recognize in the broadcast code whether the program signal is being received over the air or from a recorded media, and (4) generate a descrambling signal from the external code, the descrambling signal being different depending on the source of the signal, and (5) output the descrambling signal to the mixer, so that the user can view programs recorded on the recorded media in partially descrambled format.

Claim 7

A television receiver adapted for use in a pay television system in which broadcast signals are scrambled comprising a tuner to receive the broadcast signal and derive a video signal therefrom; a decoder circuit connected to receive the video signal from the tuner; a mixer to combine the output of the decoder circuit with a component of the output of the tuner; a television screen and associated driver circuitry to display the output of the mixer; an electrically alterable memory module containing a first memory portion in which at least one pre-written external code is carried; and a microprocessor in the decoder circuit programmed to (1) read the external code from the memory module, (2) derive a broadcast code from the video signal, (3) recognize in the broadcast code whether the program signal is being received over the air or from a recorded media, and (4) generate a descrambling signal from the external code, the descrambling signal being different depending on the source of the signal, and (5) output the descrambling signal to the mixer, so that the user can view programs recorded on the recorded media in partially descrambled format.