Abstract: A transit includes a first rotational member provided with a collimator and supported on the transit for rotation about a predetermined axis, a second rotational member supported on the transit for rotation about the predetermined axis, a detector for generating a pulse in accordance with a predetermined angle of displacement between the first rotational member and the second rotational member, a first counter for counting the number of pulses from the detector, the maximum countable pulse number of the first counter corresponding to the angle of 360.degree., the first counter generating a pulse in accordance with its counting of the maximum pulse number, and a second counter for counting the pulses from the first counter means up to a predetermined number.

Abstract: A conventional position detecting device for determining the position of a pattern having light and dark areas projected on a image sensor, in which the output signal from the image sensor is converted into a quantized signal through a sample and hold circuit. An improvement according to the invention is provided with a filter for cutting off the frequency components of the quantized signal above a clock frequency used for reading photoelectric outputs in the image sensor to convert the quantized signal into an analog signal to be used for determining the position of the pattern, whereby a high resolving power not limited by the length of each element of the image sensor is achieved.

Abstract: A device for dividing two sine signals out of phase with each other obtained from a detector in accordance with a position change and to enable a greater resolution and accuracy in the determination of displacement comprises a division circuit connected to the detector to provide an output representative of the ratio of the two sine signals, and conversion means for causing the output of the division circuit to correspond to a displacement.

Abstract: A survey instrument having an alidade portion and a fixed portion rotatably holding the alidade portion. The survey instrument comprises a light-emitting portion provided in at least one of the alidade portion and the fixed portion, a light-receiving portion provided in the other of the alidade portion and the fixed portion so as to make a pair with the light-emitting portion, and a transmission optical system for directing to the light-receiving portion the beam emitted from the light-emitting portion.

Abstract: An apparatus for measuring the amount of relative displacement of mutually facing electrodes in such a direction as to cause a change in the distance therebetween, comprises:a power source generating an AC signal of a determined frequency;a phase-shifting means comprising a resistor and the mutually facing electrodes, the phase-shifting means being adapted to apply the AC signal to the mutually facing electrodes through the resistor and to generate an output signal of which the phase is shifted in response to the amount of relative displacement of the mutually facing electrodes; anda phase difference measuring means for measuring phase difference between the output signal of the phase-shifting means and the AC signal and generating a signal corresponding to the amount of relative displacement of the mutually facing electrodes.