公开(公告)号：US3839602A

公开(公告)日：1974-10-01

申请号：US25611472

申请日：1972-05-23

Applicant: VICTOR COMPANY OF JAPAN

Inventor： TAKAHASHI N

IPC: H04S3/00 ,  G11B3/00 ,  G11B3/74

CPC classification number: H04S3/006

Abstract: A system records a four channel record by forming sum and difference signals for each two of four channel signals. The difference signals are compressed, but only with respect to a specific frequency or frequencies in the vicinity thereof. The signals thus compressed are modulated in a difference anglemodulation mode, with a specific frequency as selected a modulation transition point. After multiplexing the sum signals and the angle-modulated difference signals are recorded. A system for reproducing four channel records of the above-described type demodulates the reproduced angle modulated difference signals. The demodulated difference signals are expanded with respect to only the specific frequency or frequencies in the vicinity thereof. Thereafter, the four individual channel signals derived from the expanded reproduced sum signals and difference signals are extracted.

Abstract translation: 系统通过为四个信道信号中的每两个形成和信号和差分信号来记录四通道记录。 差分信号被压缩，但是仅针对其附近的特定频率或频率。 如此压缩的信号以差分角度调制模式被调制，其中特定频率被选择为调制转变点。 在复用之后，记录和信号和角度调制差分信号。 用于再现上述类型的四个通道记录的系统解调再现的角度调制差分信号。 解调的差分信号仅相对于其附近的特定频率或频率而扩展。 此后，提取从扩展再现和信号和差信号导出的四个单独信道信号。

公开(公告)号：US3854098A

公开(公告)日：1974-12-10

申请号：US32602773

申请日：1973-01-23

Applicant: VICTOR COMPANY OF JAPAN

Inventor： TAKAHASHI N ,  SATO M ,  IWASAKI Y ,  NISIKAWA K

IPC: H04S3/00 ,  H03D3/18 ,  G11B3/04

CPC classification number: H04S3/006

Abstract: A demodulation system employs a phase locked loop. A multichannel disc demodulation circuit has a phase comparator of a differential amplifier type having an input circuit the input AC impedance of which is set at a relatively high value. The DC impedance of a base-bias circuit of input transistors of the phase comparator is set at a relatively low value. This demodulation circuit is capable of accomplishing demodulation without the occurrence of a phase difference when an amplitude variation occurs in the envelope of an angle-modulated wave introduced as input into the phase comparator.

Abstract translation: 解调系统采用锁相环。 多通道光盘解调电路具有差分放大器类型的相位比较器，该相位比较器具有其输入AC阻抗被设置为相对高的值的输入电路。 相位比较器的输入晶体管的基极偏置电路的直流阻抗被设定为相对较低的值。 当在作为相位比较器的输入引入的角度调制波的包络中发生振幅变化时，该解调电路能够进行解调而不发生相位差。

公开(公告)号：US3795876A

公开(公告)日：1974-03-05

申请号：US3795876D

申请日：1972-04-04

Applicant: VICTOR COMPANY OF JAPAN

Inventor： TAKAHASHI N ,  ITOH Y ,  FUJITA Y ,  NISHIKAWA K ,  ISHIGAKI Y

IPC: H03G9/18 ,  H04B1/64

CPC classification number: H03G9/18

Abstract: A compression and/or expansion system comprises fixed frequency characteristic changing means having a specific fixed frequencyresponse characteristic which increases or decreases the level of an input signal in a predetermined frequency band. A variable frequency characteristic changing means has a characteristic which varies so that it approaches a characteristic complimentary with the characteristic of the fixed frequency characteristic change means as the level of the input signal becomes larger and approaches a flat characteristic as the level of the signal becomes smaller. The signal is effectively compressed or expanded according to its level by passing through the fixed and variable frequency characteristic change means.

Abstract translation: 压缩和/或扩展系统包括具有特定固定频率响应特性的固定频率特性改变装置，其增加或减少预定频带中的输入信号的电平。 可变频率特性改变装置具有随着信号电平变大而接近与固定频率特性改变装置的特性互补的特性的特性，随着信号电平变小而变得平坦特性 。 信号通过穿过固定和可变频率特性改变装置根据其电平被有效地压缩或扩大。