公开(公告)号：EP0171408B1

公开(公告)日：1990-06-13

申请号：EP85900722.1

申请日：1985-02-04

申请人： BRITISH BROADCASTING CORPORATION ,  Etablissement Public de Diffusion dit "Télédiffusion de France" ,  ETAT FRANCAIS représenté par le Ministre des PTT (Centre National d'Etudes des Télécommunications) ,  INDEPENDENT BROADCASTING AUTHORITY ,  THE MARCONI COMPANY LIMITED ,  Philips Electronics N.V. ,  THE PLESSEY COMPANY plc

发明人： BEKER, Henry, Joseph Racal Research Limited ,  BOES, Luc, Emiel, Lucien ,  BRENNAND, Peter, Robert ,  BROWN, Edmund, Raphael ,  CROWTHER, Gerald, Offley ,  DORN, Wilhelmus, Martinus Building BA ,  EDWARDSON, Stanley, Makinson ,  ELY, Stephen, Robert ,  GUILLOU, Louis, Claude ,  JENNER, Peter, Michael Marconi Secure Radio ,  JENNINGS, Sylvia, Mary Racal Research Limited ,  KNEE, Michael, James BBC Research Department ,  MASON, Arthur, Gordon ,  NICOLAS, Jean-Marie, Christophe Laboratoire

IPC分类号： H03K3/84 ,  H04N7/167

CPC分类号： H03K3/84 ,  H04N7/1675

摘要： A pseudo-random binary sequence generator comprises at least one shift register (S, T) arranged in a recirculating loop and having a plurality of logic gates (G) for logically combining the outputs of selected stages of the register to provide a pseudo-random sequence, and a multiplexer (M), having a p data inputs and q address inputs all connected to selected shift register stages, and which selects at any instant one of the p data input bits in accordance with the q-bit address word to provide the generator output. The number s of logic gates is especially high and is related to the total number r of shift register stages (r > p + q) by the expression: 2s >= r2. Some of the shift register stages of the or each shift register are connected to selected data inputs of the multiplexer and others of the stages of the same shift register are connected to selected address inputs of the multiplexer. Switches (SW1-SW4) are provided for regularly loading a re-initialisation word into the shift register(s), and this re-initialisation word can be formed by an arrangement (Fig. 4) which combines a control word with the frame count.