Optoelectric distance measuring apparatus with a time discriminator for the accurate detection of electric pulse sequence

In an optoelectric distance measuring apparatus comprising means for emitting light pulses;

• means for receiving said emitted light pulses;
• means directing a first portion of said emitted light pulses toward a target for reflection by said target and thereafter for reception by said light receiving means, and a second portion of said emitted light pulses directly into said light receiving means;
• a photodiode disposed downstream of said light receiving means, for converting said received light pulses to electric pulse signals;
• a primary comparator receiving said electric pulse signals emitted by said photodiode, said primary comparator having a positive and a negative pulse input;
• means for generating clock pulses, having a gate time controlled by said primary comparator;
• a counter to which said generated clock pulses are gated;
• said primary comparator being adapted to be connected to a source of offset voltage;
• a differentiating circuit connected between said photodiode and said negative pulse input of said primary comparator;
• and a delay line connected between said photodiode and said positive pulse input of said primary comparator;
• the improvement in which a minimum comparator is connected between said photodiode and said positive input of said primary comparator, said minimum comparator being adapted to regulate offset voltage from a said source thereof;
• and additional delay lines are respectively connected to said positive and negative pulse inputs of said comparator.