[go: up one dir, main page]

GB1500743A - Decoder for a scrambled tv signal - Google Patents

Decoder for a scrambled tv signal

Info

Publication number
GB1500743A
GB1500743A GB3714675A GB3714675A GB1500743A GB 1500743 A GB1500743 A GB 1500743A GB 3714675 A GB3714675 A GB 3714675A GB 3714675 A GB3714675 A GB 3714675A GB 1500743 A GB1500743 A GB 1500743A
Authority
GB
United Kingdom
Prior art keywords
audio
sine wave
scrambled
carrier
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3714675A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oak Industries Inc
Original Assignee
Oak Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oak Industries Inc filed Critical Oak Industries Inc
Publication of GB1500743A publication Critical patent/GB1500743A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/16—Analogue secrecy systems; Analogue subscription systems
    • H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
    • H04N7/171—Systems operating in the amplitude domain of the television signal
    • H04N7/1713—Systems operating in the amplitude domain of the television signal by modifying synchronisation signals

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

1500743 Scrambled TV reception OAK INDUSTRIES Inc 9 Sept 1975 37146/75 Heading H4R A television signal, scrambled by the addition to the audio and video carriers of a sine wave of greater amplitude on the audio than the video carrier, is descrambled by an RF amplifier 28 having a gain-controlling input receiving a sine wave derived by a detector 48, filter 42, 46 and amplifier 52 from the audio carrier. The video carrier is almost totally corrected but a residual audio carrier distortion remains. The 15À75 kHz added sine wave suppresses horizontal sync. pulses in the TV signal and is omitted during the vertical sync. and equalizing pulse intervals. The receiver shown includes conventional IF stages 12-26 for cable television in unused channels of which the one above that selected at 12 is removed in trap 30. In Fig. 2 (not shown) the descrambler without the cable channel conversion stages 12, 14 is in parallel with a direct path for non-subscription programmes.
GB3714675A 1974-03-15 1975-09-09 Decoder for a scrambled tv signal Expired GB1500743A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US45149074A 1974-03-15 1974-03-15

Publications (1)

Publication Number Publication Date
GB1500743A true GB1500743A (en) 1978-02-08

Family

ID=23792432

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3714675A Expired GB1500743A (en) 1974-03-15 1975-09-09 Decoder for a scrambled tv signal

Country Status (7)

Country Link
BE (1) BE826727A (en)
CH (1) CH575694A5 (en)
DE (2) DE2510348C2 (en)
FI (1) FI67284C (en)
FR (1) FR2264448B1 (en)
GB (1) GB1500743A (en)
NL (1) NL7502883A (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH575694A5 (en) * 1974-03-15 1976-05-14 Oak Industries Inc
FR2385281A2 (en) * 1974-03-15 1978-10-20 Oak Industries Inc Decoder for subscription cable TV system - removes sinusoidal noise signal unequally from audio and video intermediate frequency signals
US4145717A (en) * 1977-05-11 1979-03-20 Oak Industries Inc. Subscription TV audio carrier recovery system
US4112464A (en) * 1977-05-11 1978-09-05 Oak Industries Inc. Subscription TV decoder logic system
US4336553A (en) * 1980-05-14 1982-06-22 Oak Industries Method of coding audio and video signals
US4353088A (en) * 1980-05-14 1982-10-05 Oak Industries, Inc. Coding and decoding system for video and audio signals

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3081376A (en) * 1959-03-23 1963-03-12 Zenith Radio Corp Subscription television system
US3333198A (en) * 1965-12-29 1967-07-25 Ampli Vision Corp Television converter for catv system
US3729576A (en) * 1971-02-08 1973-04-24 Optical Sys Corp Encoding and decoding system for catv
CH575694A5 (en) * 1974-03-15 1976-05-14 Oak Industries Inc

Also Published As

Publication number Publication date
FI750683A (en) 1975-09-16
DE2510348A1 (en) 1975-09-18
FR2264448B1 (en) 1979-03-30
DE2510348C2 (en) 1983-11-03
BE826727A (en) 1975-06-30
CH575694A5 (en) 1976-05-14
FR2264448A1 (en) 1975-10-10
DE2711756C2 (en) 1984-03-01
FI67284C (en) 1985-02-11
DE2711756A1 (en) 1978-09-21
NL7502883A (en) 1975-09-17
FI67284B (en) 1984-10-31

Similar Documents

Publication Publication Date Title
US3081376A (en) Subscription television system
KR950006240B1 (en) Agc in sound channel of system for processing a scrambled video signal
US4024575A (en) Catv sine wave coding system
CA1175553A (en) Coding and decoding system for video and audio signals
CA1275727C (en) System for processing a scrambled video signal
US4922532A (en) Sync suppression scrambling and descrambling of television signals for subscription TV
US4424532A (en) Coding and decoding system for video and audio signals
US4706285A (en) Automatic gain control of a scrambled video signal
DE3163187D1 (en) High-definition television system
US5208659A (en) Method and apparatus for independently transmitting and recapturing clock recovery burst and DC restoration signals in a MAC system
GB1500743A (en) Decoder for a scrambled tv signal
US4329714A (en) Audio distortion eliminator
US4463376A (en) Television signal processing system for a wireless pay system
US2567545A (en) Subscription-type television receiver
ES8201790A1 (en) Television receiver for receiving a picture carrier whose amplitude is modulated with a video signal, and a sound carrier whose frequency is modulated with an audio signal
US5272751A (en) Pay television
US2993959A (en) Secrecy communication system
US2987576A (en) Secrecy communication system
KR920002840B1 (en) TV voice detector
DE3162161D1 (en) Television receiver with a sound channel operating with the carriers-difference system
ES402133A1 (en) Recording television signals
JPS594281A (en) Slice level control circuit in character signal extracting circuit
KR910002609B1 (en) Streamlined system with voice encryption
JP2832961B2 (en) CATV transmission system
NL7704112A (en) Cable TV system with converter, coder and de-scrambler - has suppressor for audio and video scrambling signal during time base period

Legal Events

Date Code Title Description
PS Patent sealed
PE20 Patent expired after termination of 20 years

Effective date: 19950908