公开(公告)号：WO1993026122A1

公开(公告)日：1993-12-23

申请号：PCT/US1993005476

申请日：1993-06-09

Applicant: SCIENTIFIC-ATLANTA, INC.

Inventor： SCIENTIFIC-ATLANTA, INC. ,  STIRLING, Ronald, C. ,  SCHUTTE, Mark, E. ,  ROBERTSON, Neil, C.

IPC: H04N07/167

CPC classification number: H04K3/825 ,  H04K3/41 ,  H04K3/42 ,  H04K2203/14 ,  H04N7/166

Abstract: An off-premises method and apparatus for the interdiction of unauthorized channels of cable television. Each subscriber module is programmable and addressable to adjust the jamming parameters of that subscriber independently of other subscribers. The subscriber module loads frequency control words corresponding to the jammed channels from a frequency control memory (404) into each latch (406-412) on a cyclic basis. The state machine (432) is adapted to vary the sequence in which frequency control words are read out of the memory (404) to modify the jamming pattern. Corresponding to each frequency control word in the memory is stored one or more mode control bits (444) which are read out contemporaneously with the frequency control words. The mode control bits (444) are used to allow a single digital to analog converter to control one or more voltage control oscillators with different frequency ranges, or to allow control of a single voltage control oscillator with multiple frequency ranges.