Title:
ROTARY HEAD TYPE INFORMATION RECORDING AND REPRODUCING DEVICE
Document Type and Number:
Japanese Patent JP3183746
Kind Code:
B2
Abstract:
PURPOSE: To lock the phase to one desired place in one rotation or plural rotations by precisely calculating a phase shift quantity over a wide area.
CONSTITUTION: A rotary head drum motor which controls the speed and phase with a phase detection signal 26 for detecting the phase once in one rotation of a head and a frequency detection signal 27 for measuring cycles of plural rotations performs phase control (D2 and D3, by a gate 9) plural times in one rotation by utilizing the signal 27 on the basis of the phase detection 26 of one rotation. Counters 7 and 5 count the signal 27 and a reference phase signal 25 which has the same frequency with it to find their difference 30. The difference is decided by using a proper threshold value and when the difference exceeds the threshold value, a proper value is added or subtracted for correction 8 to calculate the phase shift quantity over a wide area. When the phase shift value is smaller than a proper threshold value, a phase error signal is fixed by the gate 8 at a proper value to limit a phase lock point.
Inventors:
Akifumi Mibe
Koji Kaniwa
Hiroya Abe
Hideo Nishijima
Yoshio Narita
Koji Kaniwa
Hiroya Abe
Hideo Nishijima
Yoshio Narita
Application Number:
JP8339293A
Publication Date:
July 09, 2001
Filing Date:
April 09, 1993
Export Citation:
Assignee:
株式会社日立製作所
International Classes:
G11B5/588; G11B15/473; H02P29/00; H02P29/20; H04N5/782; H04N5/7826; (IPC1-7): G11B15/473; H04N5/7826
Domestic Patent References:
| JP3203852A | ||||
| JP423259A | ||||
| JP4163758A | ||||
| JP4345952A |
Attorney, Agent or Firm:
Kenjiro Take (7 outside)