1. Field of the Invention
The present invention relates to a circuit for generating a position signal, and more particularly to a circuit for generating a position signal which is able to produce a signal in digital form corresponding to the position of an object under detection.
2. Description of the Prior Art
In general, in the conventional position detecting circuit for generating an electric signal corresponding to the position of an object, as shown in U.S. Pat. No. 4,358,762 or Japanese Patent Publication No. Sho 56-46402, for example, a sinusoidal wave signal is applied to a series circuit consisting of a reference coil and a detecting coil which is connected with a member whose position is to be detected so as to vary its inductance in accordance with the position of the member and the sinusoidal wave signal developed across the detecting coil, the level of which corresponds to the position of the member, is converted into a corresponding d.c. voltage signal which is output as a position signal.
However, when such a position detecting circuit is employed in a control system using a microprocessor, it is necessary to provide an analog-digital converter for converting the d.c. voltage signal produced from the position detecting circuit into a corresponding signal in digital form. Consequently, the circuit arrangement of the position detecting circuit becomes complex and the manufacturing cost increases.
Moreover, in the conventional position detecting circuit, the level of the d.c. output voltage showing the position of the object under detection is liable to change due to the change in ambient temperature, so that the detecting accuracy of the position detecting circuit is low.