Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
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
Adaptive known signal canceller
Image processing apparatus, control method for the same, and storage medium
Analysis of stress impact on transistor performance
Catalyst composition comprising shuttling agent for ethylene multi-block copolymer formation
Implantable device
Level shifter and method of using the same
Patterned MR device with controlled shape anisotropy
  Randomly Featured Patents
Apparatus for controlling variable delivery hydraulic motor upon hydraulically operated vehicle
Heat flux meter
Voltage-programming scheme for current-driven AMOLED displays
Thin film transistors and semiconductor constructions
Toilet
Truck tool
External coat pocket for luggage
Laser system and processing conditions for manufacturing bioabsorbable stents
Sphygmomanometer aid
Video data retrieval method for use in video server environments that use striped disks