公开(公告)号：US4933749A

公开(公告)日：1990-06-12

申请号：US310792

申请日：1989-02-14

申请人： Johannes P. M. Van Lammeren ,  Armand M. Stuivenwold ,  Henricus T. P. J. Van Elk ,  Bruno P. J. M. Motte

发明人： Johannes P. M. Van Lammeren ,  Armand M. Stuivenwold ,  Henricus T. P. J. Van Elk ,  Bruno P. J. M. Motte

IPC分类号： H04N9/00 ,  H04N9/64

CPC分类号： H04N9/642

摘要： A PAL-NTSC color television standard identification circuit, comprising a first demodulation circuit (7) for a reference component and a second demodulation circuit (11) for a possible color identification component of a color synchronizing signal, can perform a reliable identification by means of a digital decoding circuit (81) for the output signals of the demodulation circuits if the second demodulation circuit (11) is adapted (41, 45, 49) to demodulate along an axis slightly differing from the axis of the color identification component (FIG. 1).

公开(公告)号：US4963831A

公开(公告)日：1990-10-16

申请号：US465561

申请日：1990-01-16

申请人： Armand M. Stuivenwold ,  Johannes P. M. Van Lammeren ,  Henricus T. P. J. van Elk ,  Bruno P. J. M. Motte

发明人： Armand M. Stuivenwold ,  Johannes P. M. Van Lammeren ,  Henricus T. P. J. van Elk ,  Bruno P. J. M. Motte

IPC分类号： H04N9/64 ,  H03B1/00 ,  H03D3/00 ,  H03D3/02 ,  H03D3/24 ,  H03D13/00 ,  H03L7/06

CPC分类号： H03D3/241 ,  H03D3/001 ,  H03B2200/0036 ,  H03B2200/0038 ,  H03B2201/02 ,  H03D13/008

摘要： Self-adjusting frequency demodulation circuit comprising a frequency demodulator (13) which is designed as an integrated circuit, the adjustment being effected with the aid of a calibration signal source (7) of one single frequency and a measuring circuit (113, 35, 101) coupled to an output (113) of the frequency demodulator (13) by controlling the output signal amplitude of the frequency demodulation circuit with a multiplier (21) which is controllable by the measuring circuit and forms part of a tuning correction circuit which optionally may further include a level shifting circuit (57). The frequency demodulation circuit is particularly suitable for use in a SECAM color television receiver, only one frequency demodulator then being required for demodulating both the two color difference signals and the identification signal.