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1. 发明专利

JP2559362B2 失效
公开(公告)号：JP2559362B2
公开(公告)日：1996-12-04
申请号：JP5583285
申请日：1985-03-22
申请人： HITACHI LTD
发明人： SUGYAMA HISATAKA , SHIGEMATSU KAZUO , MAEDA TAKESHI , SAITO ATSUSHI , TAKASUGI KAZUO
IPC分类号： G11B7/00 , G11B7/0045 , G11B7/013 , G11B7/125 , G11B7/126 , G11B11/105 , G11B20/08 , G11B20/10 , G11B20/14

2. 发明专利

JPH08138325A FREQUENCY DETECTION-TYPE DEMODULATION DEVICE 失效
公开(公告)号：JPH08138325A
公开(公告)日：1996-05-31
申请号：JP24513095
申请日：1995-08-31
申请人： K D ELECTRON INC
发明人： KOO SU YON
IPC分类号： G11B20/14 , G11B20/08 , H04L25/49 , H04L27/156
摘要： PROBLEM TO BE SOLVED: To obtain a frequency detection system demodulator which can reads out a normal data even after occurrence of an error by receiving an F-2 system rectangular wave and demodulating a clock signal RCL and a data signal RDT providing the grounds for data detection. SOLUTION: A borrow signal generating means 700 comprises a 5/7 clock generating section 701 which receives a clock pulse from an oscillator 2 and generates a clock pulse having frequency equal to 5/7 that of the clock pulse. The borrow signal generating means 700 further comprises an up-counter 702 and a down-counter 703 for counting up and down the clock signals outputted from the oscillator 2 and the 5/ 7 clock generating section 701 from 0 to 99, for example, during the interval between the edges of a clock edge pulse CL generated from an RDT generating section. Furthermore, a counter reset section 705 resets the count to '0' so that the up/down counters 702, 703 can count the next bit section when a next clock edge outputted from the RDT generating section is detected.

3. 实用新型

JPH0341323Y2 失效
公开(公告)号：JPH0341323Y2
公开(公告)日：1991-08-30
申请号：JP11940083
申请日：1983-07-30
IPC分类号： G11B20/00 , G11B20/08 , G11B20/10 , H04N5/92 , H04N5/922

4. 发明专利

JPH02170617A WAVEFORM SHAPING DEVICE FOR PWM SIGNAL 失效
公开(公告)号：JPH02170617A
公开(公告)日：1990-07-02
申请号：JP32413788
申请日：1988-12-22
申请人： MATSUSHITA GRAPHIC COMMUNIC
发明人： ONO MOTOYASU
IPC分类号： G11B20/08 , H03K5/08 , H04L25/03
摘要： PURPOSE:To correctly reproduce the duty ratio of an original signal by automatically regulating a threshold to binarize a PWM signal according to the characteristic of asymmetrical distortion of the PWM signal wherever reference signal at the duty ratio 50% is inputted. CONSTITUTION:When the waveform of a PWM signal (a) outputted from a buffer 1 is symmetrical, the output (b) of a band erasing filter 5 is approximately zero, and a smoothing output (c) is approximately the same as a zero level. Consequently the symmetrical PWM signal (a) at the duty ratio 50% is binarized by a comparator 3, and shaped to a square wave at the duty ratio 50%. When the signal is asymmetrical and offset, the output (b) of the band erasing filter 5 becomes the pulsation at an amplitude corresponding to the offset, and the smoothing output (c) becomes the continuous direct current level corresponding to the offset. Since the smoothing output (c) is made into the threshold of the comparator 3, the square wave signal at the duty ratio 50% can be obtained as well.

5. 发明专利

JPH02105368A PWM REPRODUCING DEVICE 失效
公开(公告)号：JPH02105368A
公开(公告)日：1990-04-17
申请号：JP25724588
申请日：1988-10-14
申请人： MITSUBISHI ELECTRIC CORP
发明人： KONDO YASUO
IPC分类号： G11B20/10 , G11B20/08
摘要： PURPOSE:To prevent the generation of the abnormal sounds, etc., by sampling and holding the pulse width reproduction signal undergone the waveform shaping and holding the level of the signal which is sampled and held right before the drop-out in a section corresponding to the drop-out. CONSTITUTION:A PWM (pulse width modulation) reproduction signal undergoes the waveform shaping via a PWM reproduction circuit 3 and is inputted to a programmable PLPF 4. At the same time, a speed data production circuit 10 counts the sampling frequency to convert this counted frequency into the set data of the cut-off frequency of PLPF 4 and 6 respectively via a PWM sampling frequency extracting circuit 8 based on the high frequency clock produced by a high frequency reproducing clock generator 9. Then the set data are sent to both PLPF 4 and 6. An S/H (sampling/holding) signal production circuit 11 detects the drop-out and produces an S/H control signal and an S/H signal to send these signals to an S/H circuit 5. The circuit 5 holds the level of the signal sampled and held right before the drop-out in a section corresponding to the drop-out section. Thus an abnormal signal waveform is never produced.

6. 实用新型

JPS6368234U 失效
公开(公告)号：JPS6368234U
公开(公告)日：1988-05-09
申请号：JP15101587
申请日：1987-10-01
IPC分类号： H04B1/66 , G11B5/09 , G11B20/08 , H04B14/04

7. 发明专利

JPS6313270B2 失效
公开(公告)号：JPS6313270B2
公开(公告)日：1988-03-24
申请号：JP14141179
申请日：1979-11-02
申请人： DISCOVISION ASS
发明人： JATSUKU HENRII BEIRII , JERARUDO HAWAADO OTAUEI
IPC分类号： G11B7/00 , G11B7/004 , G11B20/08 , G11B20/10 , G11B20/12 , G11B20/14 , H03M13/00 , H04B14/04 , H04L25/49 , H04N5/92 , H04N5/926

8. 发明专利

JPS5830648B2 失效
公开(公告)号：JPS5830648B2
公开(公告)日：1983-06-30
申请号：JP7442775
申请日：1975-06-20
申请人： HITACHI LTD
发明人： SAGAWA AKIO
IPC分类号： G11B20/08 , G11B5/09 , G11B20/12 , G11B20/14

9. 发明专利

JPS5769509A Magnetic recorder and reproducer 失效
标题翻译：磁记录器和复印机
公开(公告)号：JPS5769509A
公开(公告)日：1982-04-28
申请号：JP14511680
申请日：1980-10-17
申请人： Olympus Optical Co Ltd
发明人： YANAGIDA TSUNEO
IPC分类号： H04N5/7826 , G11B5/02 , G11B20/08 , G11B20/22 , H04N5/92
CPC分类号： H04N5/92 , G11B20/08 , G11B20/225
摘要： PURPOSE: To improve the signal transmission quality of the transmission of a still picture signal by enabling direct recording on recording medium by performing the vertical magnetic recording of a signal after analog pulse modulation.
CONSTITUTION: The output terminal of a modulator 14 or demodulator 20 is connected to a vertical magnetic recording head 26 via a recording-head driving circuit 25. A head 26 magnetizes a magnetic recording medium 27 having magnetic anisotropy with a small angle of dispersion. The pulse-interval-modulated PDM signal from the modulator 14 is amplified through the recording-head driving circuit 25 so that an enough recording current is flowed to the recording head 26. The recording head 26 performs the vertical magnetic recording of the PDM signal on a vertical magnetic anisotropic recording medium 27 driven by a recording-medium driver 28. Consequently, direct recording on the recording medium is enabled and accurate pulse positions are secured, so the quality of the transmission of a still picture signal is improved.
COPYRIGHT: (C)1982,JPO&Japio
摘要翻译：目的：通过在模拟脉冲调制之后执行信号的垂直磁记录，通过在记录介质上直接记录来提高静止图像信号传输的信号传输质量。构成：调制器14或解调器20的输出端经由记录头驱动电路25连接到垂直磁记录头26.磁头26利用小的分散角来磁化具有磁各向异性的磁记录介质27。来自调制器14的脉冲间隔调制的PDM信号通过记录头驱动电路25被放大，使得足够的记录电流流到记录头26.记录头26执行PDM信号的垂直磁记录由记录介质驱动器28驱动的垂直磁性各向异性记录介质27.因此，可以使记录介质上的直接记录能够确保精确的脉冲位置，从而提高了静止图像信号的传输质量。

10. 发明专利

JPS553219A SOUND RECORDING*REPRODUCING METHOD VIA PULSE MODULATION 失效
公开(公告)号：JPS553219A
公开(公告)日：1980-01-11
申请号：JP7543878
申请日：1978-06-23
申请人： ODAGIRI TAKASHI
发明人： ODAGIRI TAKASHI
IPC分类号： H03K9/08 , G11B20/08 , H03K7/08 , H03K11/00 , H04B14/02
摘要： PURPOSE:To ensure an assured reproduction by recording the clock signals simultaneously at the sound recording via the PWM modulation. CONSTITUTION:For example, the signals from pulse oscillation circuit (a) of 50K HZ are put into PWM modulation circuit (g) after processes including the integration, amplification and others. The audio signals are also put into circuit (g) and then put into MIX after modulation and division. On the other hand, the signals from circuit (a) are divided down to 1/4 through circuits (d) and (e) to be put into MIX and then to be mixed with the above mentioned modulation signals. These modulation signals underwent the 1/2 division, and thus their isolation is easy from the synchronous signals. As a result, an assured reproduction is secured to be applied effectively to the sound recording/reproduction of the normal recorder and the like.

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