公开(公告)号：WO1989008966A1

公开(公告)日：1989-09-21

申请号：PCT/US1989000907

申请日：1989-03-10

Applicant: SCIENTIFIC-ATLANTA, INC.

Inventor： SCIENTIFIC-ATLANTA, INC. ,  WEST, Lamar, E., Jr. ,  PLONSKY, Christopher, B. ,  FARMER, James, O. ,  DURAND, David, P.

IPC: H04N07/167

CPC classification number: H04K3/825 ,  H04K3/28 ,  H04K3/42 ,  H04K3/43 ,  H04K3/86 ,  H04K2203/14 ,  H04N7/166

Abstract: Off premises cable television interdiction apparatus comprises a microprocessor actuation and control means (300) for actuating and controlling a plurality of frequency agile voltage controlled oscillators (341). The voltage controlled oscillators selectively jam only unauthorized premium programming transmitted in the clear from a head end to a particular subscriber. Each voltage controlled oscillator is allocated a continuous band of frequencies consistent with the elimination of jamming signal frequency hamonics which may disturb authorized programming at a higher channel frequency. The microprocessor actuation and control means provides a calibration mode and a normal mode of operation. During the normal mode of operation, a frequency hopping rate on the order of four thousand hertz is achievable. The method of interdiction comprises the steps of generating and storing voltage control words for operating the oscillators consistent with a head end selected jamming factor for a particular channel to be jammed and addressably transmitting and storing premium programming authorization data.

公开(公告)号：WO1985005710A1

公开(公告)日：1985-12-19

申请号：PCT/US1985001029

申请日：1985-05-31

Applicant: SCIENTIFIC-ATLANTA, INC.

Inventor： SCIENTIFIC-ATLANTA, INC. ,  HAMMETT, Geoffrey, G.

IPC: G06F15/46

CPC classification number: G01D5/2291 ,  F15B11/048 ,  F15B15/2861 ,  F15B2211/212 ,  F15B2211/3057 ,  F15B2211/31558 ,  F15B2211/31576 ,  F15B2211/328 ,  F15B2211/35 ,  F15B2211/6313 ,  F15B2211/6336 ,  F15B2211/665 ,  F15B2211/7053 ,  F15B2211/755 ,  G05B19/353 ,  G05B2219/34002 ,  G05B2219/34003 ,  G05B2219/34215 ,  G05B2219/37019 ,  G05B2219/37133 ,  G05B2219/37399 ,  G05B2219/37491 ,  G05B2219/39466 ,  G05B2219/41301 ,  G05B2219/42115 ,  G05B2219/42123 ,  G05B2219/42237

Abstract: A linear servoactuator including an integrated split-secondary differential transformer position sensor (11) and a fluid driven linear actuator (10) controlled by solenoid poppet valves (V1-V4). Signals from the position sensor transformer (11) are digitized and linearized by a control microcomputer (40) by using digitized transformer signals as addresses for a programmable read only memory (50). The linearized output is compared to a command position to determine an error value. When the error reaches a predetermined magnitude, indicating that the actuator is approaching the command position, solenoid poppet valves (V1-V4) are actuated by a pulse-width modulated signal from the microcomputer (40) to progressively decrease the fluid flow to the actuator for deceleration.