Title:
ELECTRONIC TACHOGRAPH DEVICE
Document Type and Number:
Japanese Patent JPH01134264
Kind Code:
A
Abstract:
PURPOSE:To prevent a speed which is recorded on a tachograph from having an error owing to variance among components, temperature variation, or a secular change by obtaining a pulse signal which has constant period width corresponding accurately to the period of a pulse signal generated by a vehicle speed sensor. CONSTITUTION:The pulse signal obtained by the vehicle speed sensor A is inputted to a detecting circuit B and its leading edge or trailing edge are detected. When the leading edge or trailing edge is detected, a counting means C is started and a pulse generating means D outputs a pulse signal with specific width prescribed by the period up to when the counted value of the counting means C reaches a specific value. This pulse signal is generated to constant width every time the vehicle speed sensor A generates a pulse, and its period varies with a vehicle speed, so this pulse signal is used to record the speed.
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Inventors:
HAGIWARA SHIGERU
Application Number:
JP29216887A
Publication Date:
May 26, 1989
Filing Date:
November 20, 1987
Export Citation:
Assignee:
YAZAKI CORP
International Classes:
G01P1/12; (IPC1-7): G01P1/12
Domestic Patent References:
| JPS5278477A | 1977-07-01 |
Attorney, Agent or Firm:
Hideo Takino