Cable television system with stereo sound reproduction
First Claim
1. In a cable television converter having tuner means for selecting and outputting one of a plurality of incoming channels containing audio and scrambled video signals, a descrambler coupled to the output of said tuner for descrambling video signals from said tuner, and means for producing and outputting a first control signal to enable or disable output of an unscrambled RF signal from said descrambler in accordance with an authorization code provided by a cable system operator;
- the improvement comprising;
first means for coupling to the output of said tuner to obtain a selected channel signal including a modulated audio carrier prior to said descrambler;
second means for coupling to the output of said first control signal means to obtain said first control signal;
means for summing the signals obtained by said first and second means into a composite signal; and
stereo adapter means coupled to receive said composite signal for;
detecting the audio signal portion of the composite signal and separating it into left and right stereo signals,extracting the first control signal from said composite signal, andoutputting the left and right stereo signals for audio reproduction upon authorization indicated by the extracted first control signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A cable television converter is retrofitted for use in reproducing stereophonic broadcast television sound. A composite signal is produced comprising the scrambled output signal from the converter tuner, the reception enable control signal from the converter'"'"'s digital processor, and the output signal from the converter'"'"'s remote control detection circuit. The composite signal is applied to a stereo adapter which separates the audio signal portion of the composite signal into left and right stereo signals, extracts the enable control signal from the composite signal, and outputs the left and right stereo signals for audio reproduction upon authorization indicated by the extracted enable control signal. Remote volume control and selection of a second audio program (SAP) is also provided.
-
Citations
19 Claims
-
1. In a cable television converter having tuner means for selecting and outputting one of a plurality of incoming channels containing audio and scrambled video signals, a descrambler coupled to the output of said tuner for descrambling video signals from said tuner, and means for producing and outputting a first control signal to enable or disable output of an unscrambled RF signal from said descrambler in accordance with an authorization code provided by a cable system operator;
- the improvement comprising;
first means for coupling to the output of said tuner to obtain a selected channel signal including a modulated audio carrier prior to said descrambler; second means for coupling to the output of said first control signal means to obtain said first control signal; means for summing the signals obtained by said first and second means into a composite signal; and stereo adapter means coupled to receive said composite signal for; detecting the audio signal portion of the composite signal and separating it into left and right stereo signals, extracting the first control signal from said composite signal, and outputting the left and right stereo signals for audio reproduction upon authorization indicated by the extracted first control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- the improvement comprising;
-
8. In a cable television converter having tuner means for selecting and outputting one of a plurality of incoming channels containing audio and scrambled video signals, and a descramler coupled to the output of said tuner for descrambling video signals from said tuner and providing an unscrambled RF signal to be coupled to a television, the improvement comprising:
-
first means for coupling to the output of said tuner to obtain a selected channel signal including a modulated audio carrier prior to said descrambler; second means for producing and outputting a first control signal containing volume control information; means for summing the signal obtained by said first means and the signal output by said second means into a composite signal; and stereo adapter means coupled to receive said composite signal for; detecting the audio signal portion of the composite signal and separating it into left and right stereo signals, extracting the first control signal from said composite signal, adjusting the amplitude of said left and right stereo signals in response to the extracted first control signal, and outputting the left and right stereo signals for audio reproduction. - View Dependent Claims (9, 10, 11)
-
-
12. In a cable television converter having tuner means for selecting and outputting one of a plurality of incoming channels containing audio and scrambled video signals, and a descrambler coupled to the output of said tuner for descrambling video signals from said tuner and producing an unscrambled Rf signal for output to a television, the improvement comprising:
-
first means for coupling to the output of said tuner to obtain a selected channel signal including modulated audio carriers prior to said descrambler; second means for producing and outputting a SAP control signal; means for summing the signal obtained by said first means and the signal output by said second means into a composite signal; and stereo adapter means coupled to receive said composite signal for; detecting stereo audio signal portions of the composite signal and separating them into left and right stereo signals, detecting an alternate audio signal carried in the composite signal, extracting the SAP control signal from said composite signal, and outputting either the left and right stereo signals or the alternate audio signal for audio reproduction in response to the status of the extracted SAP control signal. - View Dependent Claims (13, 14)
-
-
15. A method for retrofitting a cable television converter for use with stereophonic broadcast television sound, said converter having tuner means for selecting and outputting one of a plurality of incoming channels containing audio and scrambled video signals, a descrambler coupled to the output of said tuner for descrambling video signals from said tuner, and means for producing and outputting a first control signal to enable or disable output of an unscrambled RF signal from said descrambler in accordance with an authorization code provided by a cable system operator, comprising the steps of:
-
tapping into the output of said tuner to obtain a selected channel signal including a modulated audio carrier prior to descrambling; tapping into the output of said first control signal means to obtain said first control signal; summing the selected channel signal with the first control signal to obtain a composite signal; coupling the composite signal to a stereo adapter; and using the stereo adapter to; detect the audio signal portion of the composite signal and separate it into left and right stereo signals, extract the first control signal from the composite signal; and output the left and right stereo signals for audio reproduction upon authorization indicated by the extracted first control signal. - View Dependent Claims (16, 17, 18, 19)
-
Specification