公开(公告)号：EP0125051A3

公开(公告)日：1985-12-18

申请号：EP84302505

申请日：1984-04-12

Applicant: VICTOR COMPANY OF JAPAN, LIMITED

Inventor： Koide, Hajime

IPC: G11B05/008 ,  H04N09/83 ,  G11B05/592 ,  G11B21/10 ,  G11B05/04 ,  G11B05/58 ,  G11B05/52 ,  H04N05/782

CPC classification number: H04N9/802 ,  G11B5/0086 ,  G11B5/5922 ,  G11B21/103 ,  H04N9/8355

Abstract: In a recording apparatus frequency modulators (25-28) a provided for modulating carriers having different frequencies with an information signal. The different frequency irriers are sequentially combined by a switch (12) and aplied to a recording head in response to the head being fifted from one track to the next to record each of the carriers a different track, so that there is a difference in frequency between carriers recorded on adjacent tracks. During play- back, the frequency-modulated carriers are sequentially produced and separated by band-pass filters (25-28) into individual carriers, frequency-demodulated respectively by (29-32) and sequentially combined by a switch 3) to form the original information signal. Tracking control (100) is provided to control the lateral position of the ansducer head in response to the carriers which are derived tracks on opposite sides of the track being scanned.

公开(公告)号：EP0101179A3

公开(公告)日：1985-09-18

申请号：EP83303976

申请日：1983-07-07

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Todd, Craig C.

IPC: G11B05/04 ,  G11B05/02

CPC classification number: G11B20/22 ,  H04N9/7908 ,  H04N9/802

Abstract: This invention reduces crosstalk interference components without a significant increase in recorded bandwidth of the modulated audio signals and without a significant degradation of the signal-to-noise ratio of the reproduced audio signals. According to the invention, the nominal carrier frequency of the modulated audio signal in adjacent tracks or scans is offset by an amount sufficient to shift the crosstalk interference components outside the desired audio pass band for substantially all modulating amplitudes and frequencies. At the same time, the modulated audio frequency spectra of the adjacent tracks substantially overlap so that additional overall bandwidth requirements are minimized. A satisfactory offset from track to track is in the order of twice the maximum audio response frequency. As the offset is reduced or as occasional high frequency high amplitude audio occurs in adjacent tracks, crosstalk distortion components will tend to appear beginning at the high frequencies. Such crosstalk interference can be further reduced by the use of frequency dependent compressor-expander noise reduction because of the audio band rather than across the entire audio band as in the case of no track-to-track carrier offset, In one example audio signals are frequency modulated and recorded on a helical scan recorder using carrier frequencies f 1 and f 2 for odd and even scans. On playback the signals from odd and even scans are processed by respective limiters 6 and 8 respective demodulators 10 and 12 and respective high pass filters 14 and 16.

Abstract translation: 本发明可减少串扰干扰成分，而不会明显增加已调音频信号的记录带宽，并且不会显着降低再生音频信号的信噪比。 根据本发明，相邻轨道或扫描中的调制音频信号的标称载波频率偏移足以将基本上所有调制幅度和频率的所需音频通带外的串扰干扰分量移位的量。 同时，相邻轨道的调制音频频谱基本上重叠，使得额外的总带宽要求最小化。 从轨道到轨道的令人满意的偏移量是最大音频响应频率的两倍。 随着偏移减小或偶尔的高频高振幅音频发生在相邻轨道中，串扰失真分量将倾向于从高频开始出现。 由于干扰定位在音频的一部分而不是整个音频带的倾向，因此使用频率相关的压缩器 - 扩展器噪声降低可以进一步降低这种串扰干扰，如在没有跟踪的情况下 曲线载波偏移。

公开(公告)号：WO1982002612A1

公开(公告)日：1982-08-05

申请号：PCT/GB1982000012

申请日：1982-01-18

Applicant: AUTOMATION FACILITIES LTD ,  KINGSBURY PHILIP CHARLES ORLANDO

Inventor： AUTOMATION FACILITIES LTD

IPC: G11B05/04

CPC classification number: G11B5/41

Abstract: La tete d'entrainement d'un disque souple est nettoyee en utilisant un disque de nettoyage (44) introduit de facon interchangeable dans une pochette de disque (10) par son bord ouvert. Seul le disque est jete lorsqu'il est souille. La pochette est adaptable aux entrainements a une face ou a deux faces a l'aide d'une feuille ou bande de couverture decollable (32) qui recouvre la fenetre de la tete (30) d'un cote de la pochette.

公开(公告)号：WO1980001964A1

公开(公告)日：1980-09-18

申请号：PCT/US1979000200

申请日：1979-04-02

Applicant: RIDDLE H

IPC: G11B05/04

CPC classification number: G11B23/0007 ,  G11B20/06 ,  G11B20/22

Abstract: An improved apparatus for reducing noise in a frequency-modulated data stream of the type utilizing a reference stream of predetermined frequency that has been subjected to essentially the same noise. In a preferred embodiment of the apparatus, the data stream is transformed by a first discriminator (52) into a first signal of value proportional to the frequency of the data stream, and the reference stream is transformed by a second discriminator (53) into a second signal that has a value proportional to the product of the reference stream frequency times a feedback value (41). The feedback value is derived from a combination of the first and second signals in a combiner (44). One of the important uses of the apparatus is in connection with frequency modulation tape recording systems.