Abstract: A two-eyed type optical distance measuring apparatus operable in accordance with a phase difference detecting process to optically measure a distance between the apparatus and an object to be measured is disclosed. To determine the distance between the apparatus and the object to be measured, a phase difference between the phase of a reflected light beam reflected from the object to be measured and the optical phase of a reference light beam derived from partial division of a distance measuring light beam emitted from a light source is detected and calculated.

Abstract: An optical distance measuring apparatus operable in accordance with a phase difference detecting process, comprises a processing system including a central processing unit and first and second local oscillating circuits which serve to detect and calculate a phase difference between the electrical phase of a modulated signal outputted from a reference oscillator electrically connected to a light source via a modulating circuit and the electrical phase of a demodulated signal outputted from a demodulating circuit electrically connected to a light receiving portion so as to determine a distance between the apparatus and an object to be measured based on the detected phase difference with reference to the electrical phase of a reference signal outputted from the reference oscillator.

Abstract: An optical distance measuring apparatus is disclosed which is operable in accordance with a phase difference detecting process wherein a processing system including a central processing unit and a digital type mix-down circuit detects and calculates a phase difference between the electrical phase of a signal output from a light receiving portion in response to receipt of a reflected light beam and the electrical phase of a reference signal output from a reference oscillator so as to determine a distance between the apparatus and a object spaced at a distance to be measured with reference to the electrical phase of a local oscillation signal output from a local oscillator. A second circuit system of the processing system on the light receiving side includes a ladder resistance type attenuation circuit, a multiplexer, an veriable gain current amplifier, a wave shape correcting circuit and a signal amplitude detecting circuit.