Abstract: An optical distance measuring equipment in which light from a light emission element is transmitted to an object through a light transmission lens, and light reflected on the object is received by a light reception element through a light reception lens so that a distance to the object is measured on the basis of light transmitting timing and light receiving timing. In the optical distance measuring equipment, a lens holding member for disposing the light transmission lens and the light reception lens substantially at the same distance relative to the light emission element and the light reception element respectively is provided in front of a light transmission/reception board on which the light emission element and the light reception element are installed.

Abstract: The present application discloses a ship collision preventive aid apparatus in which a radar picture and a key picture are selected from all pictures displayed on a display means as transmitted through a touch panel, and the operator touches the surface of the touch panel, so that a program for an operation key name selected is executed. Predetermined collision preventive aid data required for collision avoidance are then displayed on a display screen.With operation simplified, appropriate information concerning collision avoidance may be supplied and the entire construction is simplified.

Abstract: A variable-narrow-band rejection filter is inserted in a reception signal path for rejecting a jamming wave. Signals at input and output terminals of the narrow-band rejection filter are picked up by a pair of first and second bandpass filters each having a center frequency that can be passed thereby which is equal to a rejection frequency of the narrow-band rejection filter. A phase difference between outputs from the bandpass filter is detected by a phase comparator, and the detected signal is supplied through a switch to a hold circuit in which the supplied signal is held. The rejection frequency of the narrow-band rejection filter is adjusted into conformity with the jamming wave frequency by an output from the hold circuit. The levels of the output signals from the first and second bandpass filters are detected respectively by a pair of first and second level detectors, and the detected outputs are compared by a comparator.

Abstract: A narrow-band rejection filter inserted in a received signal path is arranged so that its rejection frequency may be changed by a control signal; the narrow-band rejection filter is controlled so that its rejection frequency may substantially coincide with the center frequency of a jamming wave; thereafter, the phase difference between signals on the input and the output side of the narrow-band rejection filter is detected; and the abovesaid narrow-band rejection filter is controlled by a signal corresponding to the phase difference so that its rejection frequency may automatically coincide with the center frequency of the jamming wave.

Abstract: A Loran receiving apparatus is repeatedly switched by the actuation of a display mode changeover means between the state of displaying a plurality of measured time differences on a display in a sequential order and the state of continuously displaying only one of the measured time differences. A Loran signal detector detects a phase code of an incoming Loran signal. The detected phase code is stored in N memory parts, each corresponding to the Loran signal repetition period. Coincidence of the outputs from the memory parts is detected as the presence of a correct Loran signal.