Information read device

• US 4,342,054 A
• Filed: 06/02/1980
• Issued: 07/27/1982
• Est. Priority Date: 06/06/1979
• Status: Expired due to Term

• Current Assignee: Nakamichi Corporation
• Original Assignee: Nakamichi Corporation
• Inventors: Kobayashi, Kozo, Terui, Nobuo
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US06/155,783
• Time in Patent Office: 785 Days
• Field of Search: 360/40, 360/43, 360/46, 360/67
• US Class Current: 360/40
• CPC Class Codes: G11B 20/1419 to or from biphase level coding, i.e. to or from codes where a one is coded as a transition from a high to a low level during the middle of a bit cell and a zero is encoded as a transition from a low to a high level during the middle of a bit cell or vice versa, e.g. split phase code, Manchester code conversion to or from biphase space or mark coding, i.e. to or from codes where there is a transition at the beginning of every bit cell and a one has no second transition and a zero has a second transition one half of a bit period later or vice versa, e.g. double frequency code, FM code

Abstract

This invention relates to an information read device for reading the information of a coded AC signal. The information read device for reading the information of a coded AC signal, wherein a bit "1" is represented by one cycle of an AC signal and a bit "0" is represented by an absence of said AC signal, comprises a first square wave converter to generate a first square wave signal corresponding to positive components of said coded AC signal, a second square wave converter to generate a second square wave signal corresponding to negative components of said coded AC signal, and gate means to selectively pass one of said first and second square wave signals so that said first square wave signal is passed when said AC signal of said coded AC signal begins with a negative component while said second square wave signal is passed when said AC signal of said coded AC signal begins with a positive component, comprising means to modify said coded AC signal so that said information is read out on a level of negative component of said coded AC signal when it begins at a positive polarity and on a level of positive component of said coded AC signal when it begins at a negative polarity.

Claims

1. An information read device for reading the information of a coded AC signal wherein a bit "1" is represented by one cycle of an AC signal and a bit "0" is represented by an absence of said AC signal comprising:

a first square wave converter to generate a first square wave signal corresponding to positive components of said coded AC signal;

a second square wave converter to generate a second square wave signal corresponding to negative components of said coded AC signal; and

gate means to selectively pass one of said first and second square wave signals so that said first square wave signal is passed when said AC signal of said coded AC signal begins with a negative component while said second square wave signal is passed when said AC signal of said coded AC signal begins with a positive component.

2. An information read device as set forth in claim 1, and wherein said gate means comprises a first NAND gate having one of inputs to which said first square wave signal is applied, a second NAND gate having one of inputs to which an output signal from said first NAND gate is applied and the other input to which said second square wave signal is applied, an output signal from said second NAND gate being applied to the other input of said first NAND gate, a third NAND gate having one of inputs to which said output signal from said first NAND gate is applied after being inverted and the other input to which said second square wave signal is applied, a fourth NAND gate having one of inputs to which said first square wave signal is applied and the other input to which said output signal from said second NAND gate is applied after being inverted, and a fifth NAND gate having inputs to which output signals from said third and fourth NAND gates are applied, respectively.