Title:
OFFSET ADJUSTMENT DEVICE
Document Type and Number:
Japanese Patent JPH04195601
Kind Code:
A
Abstract:
PURPOSE:To obtain necessary resolution in an A/D converter with low bit precision by determining the pulse width of the PWM signal by an arithmetic unit and indicating it to a PWM signal generator, and obtaining an offset adjusting voltage from its generated PWM signal and adjusting the offset of an input signal at all times. CONSTITUTION:The arithmetic unit 12 reads the offset value of the input signal out of a signal sent from the A/D converter 11 and indicates the pulse width of the PWM signal to the PWM signal generator 14 so as to adjust the offset. The PWM signal generated by the PWM signal generator 14 with the indication is passed through a low-pass filter 15 and converted into the specific offset adjusting voltage, which is used by a differential amplifier 16 to adjust the offset. Consequently, the input signal which has the offset need not be in the A/D conversion range of the A/D converter 11 at any time and the A/D conversion range is small, so high resolution is obtained.
Inventors:
ASAKA KOICHI
Application Number:
JP33244190A
Publication Date:
July 15, 1992
Filing Date:
November 28, 1990
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G05B1/02; H03F3/34; H03F3/347; (IPC1-7): G05B1/02; H03F3/34
Attorney, Agent or Firm:
Akira Kobiji (2 outside)