Rotational position detecting device having peak and bottom hold circuits

A rotational position detecting device connected to an electric power source through a switch for detecting rotational position of a rotating member of an engine comprising:

• a rotor having a plurality of projections and connected to said rotating member;
• a signal generator for generating alternating signal in response to movement of said projections;
• an amplifier connected to said signal generator for amplifying said alternating signal;
• a peak hold circuit for holding a maximum value of said alternating signal;
• a bottom hold circuit for holding a minimum value of said alternating signal;
• a first member for generating a first threshold value based on said maximum value;
• a second member for generating a second threshold value based on said minimum value;
• a first comparator connected to said amplifier and said first member for generating a reset signal when said alternating signal becomes lower than said first threshold value;
• a second comparator connected to said amplifier and said second member for generating a set signal when said alternating signal becomes higher than said second threshold value;
• a flip-flop circuit connected to first and second comparators for generating a rotational base signal;
• an output circuit;
• and
• means connected between said flip-flop circuit and said output circuit for invalidating said rotational base signal until one of said set signal and said reset signal is first generated after said switch is closed.

A wave shaping circuit connected to an electric power source through a switch for converting an alternating analog signal to a rectangular signal comprising:

• a peak hold circuit for holding a maximum value of said alternating analog signal;
• a bottom hold circuit for holding a minimum value of said alternating analog signal;
• a first member for generating a first threshold value based on said maximum value;
• a second member for generating a second threshold value based on said minimum value;
• a first comparator connected to said signal generator and said first member for generating a reset signal when said alternating signal becomes lower than said first threshold value;
• a second comparator connected to said signal generator and said second member for generating a set signal when said alternating signal becomes higher than said second threshold value;
• a flip-flop circuit connected to first and second comparators for generating a rotational base signal;
• an output circuit;
• and
• means connected between said flip-flop circuit and said output circuit for invalidating said rotational base signal when one of said set signal and said reset signal is first generated after said switch is closed.

A rotational position detecting device connected to an electric power source through a switch comprising:

• a signal generator connected to a rotating member of an engine for generating alternating magnetic flux signal;
• a converter circuit connected to said signal generator for converting said magnetic flux signal to an alternating electric signal;
• a comparator circuit connected to said converter for generating a reset signal when said alternating electric signal becomes lower than a reset level and a set signal when said alternating electric signal is higher than a set level;
• a flip-flop circuit connected to said comparator for generating a signal having two levels which turn over each time said set and reset signals are applied thereto;
• an output circuit;
• and
• means connected between said flip-flop circuit and said output circuit for interrupting said signal of said flip-flop circuit unchanged until said set signal is first applied thereto after said switch is closed and said reset signal is first applied thereto.