Resources Contact Us Home
Coding system for pay television apparatus

Image Number 5 for United States Patent #4025948.

At the sending end, a plurality of high-frequency oscillators each furnish a signal having a frequency different from the frequency of the other of the oscillators. Timing signals derived from the television signal and signals from a random pulse generator are combined to furnish enabling signals for enabling the high-frequency oscillators during predetermined time intervals of the television signal and in a random order. A logic circuit which includes externally operable switches for setting up a program code assignment receives the enabling signals and furnishes an encoder control signal only in response to certain selected enabling signals. The encoder control signal changes the polarity of the picture signals relative to the synchronizing signals in the television signal. A mixer mixes the oscillator signals into the encoded television signal. At the decoder the oscillator signals are filtered out, and a logic circuit set up in accordance with a punch card having a program corresponding to the code assignment at the encoder furnishes a decoder control signal which causes a reversal of the polarity of the picture signals thereby reestablishing a standard television signal.

  Recently Added Patents
Fuel cell support structure
Synthesis of amines and intermediates for the synthesis thereof
Image enhancement based on multiple frames and motion estimation
Method and apparatus for sensing an input object relative to a sensing region of an ultrasound sensor device
System, method, and computer program product for determining whether an electronic mail message is compliant with an etiquette policy
Beaconing and superframe structure for millimeter wave wireless technologies
Detection system and method for mobile device application
  Randomly Featured Patents
Anti-syphon freezeless water hydrant
Body frame structure of railway vehicle
Process for producing a gasoline blending component and a middle distillate by adjusting a level of a halide containing additive during alkylation
Digital-to-analog converter image suppression with hilbert transform
Flea leucine aminopeptidase nucleic acid molecules and uses thereof
Substrate connector
Hydrocodone therapy
Apparatus for and method of comminuting agglomerates
Vehicle front lower grille
Olefin polymerization catalysts