Apparatus for encoding of information

• US 4,329,711 A
• Filed: 11/06/1979
• Issued: 05/11/1982
• Est. Priority Date: 02/20/1979
• Status: Expired due to Term

• Current Assignee: Payview Limited
• Original Assignee: Payview Limited
• Inventors: Cheung, William S. H.
• Primary Examiner(s): Buczinski, S. C.
• Application Number:
  US06/091,781
• Time in Patent Office: 917 Days
• Field of Search: 358/114, 358/122, 358/123, 358/116, 455/27
• US Class Current: 380/34
• CPC Class Codes: H04K 1/003 by varying carrier frequency at or within predetermined or random intervals H04K1/04 takes precedence
• CPC Class Codes: H04N 7/167 Systems rendering the television signal unintelligible and subsequently intelligible

Abstract

Information encoding apparatus comprises at least two modulators, each operating on a different channel, means for combining the outputs of the modulators, means for applying an information signal to the modulators for modulating the carrier waves in their channels according to the information signal, a random data terminal and means responsive to the random data signal to enable the combining means to receive a carrier wave modulated with said information from individual modulators in turn. The invention also includes transmitting apparatus for transmitting the encoded information together with a signal from the random data terminal and the invention also includes receiving apparatus for receiving and decoding the information under the control of the random data signal extracted from the received signal.

Claims

1. An apparatus for encoding an information signal in accordance with a data signal comprising:

means for inverting said data signal;

a first pair of gates each having an input connected to receive a noise signal, a control input, and an output, one of said control inputs connected to receive said data signal, the other of said control inputs connected to receive an inverted data signal from said means for inverting;

a second pair of gates each having an input connected to receive said information signal, a control input, and an output, one of said control inputs connected to receive said data signal, the other of said control inputs being connected to receive an inverted data signal from said means for inverting;

a first OR gate for combining the output of said gate of said first pair of gates which is controlled by said data signal and the output of said gate of said second pair which receives an inverted data signal; and

a second OR gate for combining the output of the gate of said first pair of gates receiving an inverted data signal and the output of the gate of said second pair receiving said data signal, said OR gates providing first and second related information signals mixed with said noise signal.

2. The apparatus of claim 1, further comprising:

a first oscillator;

a second oscillator;

a first modulator for modulating a signal from said first oscillator with a signal from said first OR gate;

a second modulator for modulating a signal from said second oscillator with a signal from said second OR gate; and

means for combining signals from said modulators with said data signal whereby a composite signal is generated.

3. The apparatus of claim 2, further comprising means for transmitting said composite signal.

4. The apparatus of claim 2, wherein said data signal randomly changes.

5. An apparatus for encoding an information signal for transmission by a radio frequency transmitter comprising:

means for supplying a data signal and an inverted data signal;

means for supplying an information signal to be encoded;

first and second combining gates;

means for gating said information signal into one input of said first combining gate in response to said data signal, and for gating a noise signal into a second input of said combining gate in response to an inverted data signal whereby an information signal combined with a noise signal in a format controlled by said data signal is generated;

means for gating said information signal into one input of said second combining gate in response to said inverted data signal, and for gating said noise signal into a second input of said second combining gate in response to said data signal;

means for modulating a first carrier wave with a signal from said first combining gate, and for modulating a second carrier wave with a signal from said second combining gate whereby first and second modulated carrier waves are produced;

means for combining said modulated carrier waves with said data signal whereby a composite signal for transmitting is produced; and

a transmitter for transmitting said composite signal.

6. An apparatus for decoding a composite signal comprising first and second carrier waves modulated with an information signal alternately combined with a noise signal according to a data signal comprising:

means for supplying said data signal, an inverted data signal

said first carrier wave, and said second carrier wave;

first and second gate means connected to receive said first carrier wave;

third and fourth gate means connected to receive said second carrier wave;

means for enabling said first and third gate means in response to said data signal and for enabling said second and fourth gate means in response to an inverted data signal;

means for combining signals produced from said first and fourth gate means to produce a single decoded signal;

and

means for combining signals produced from said second and third gate means to produce a second decoded signal, one of said decoded signals being substantially free of noise.