Abstract: Problems The present invention relates to a distance measuring device that measures the distance between a single signal transmitting means and a single signal receiving means with high accuracy by the signal transmitting means transmitting radio frequency signals. Means for Solving the Problems A distance measuring device is comprised of a signal transmitting means (101), a signal receiving means (102) and a signal processing means (103). The signal transmitting means transmits radio frequency signals, the components of which are a plurality of measuring signals in synchronization with an output reference signal of a reference oscillator (7).

Abstract: A distributed antenna for use in a digital mobile telephone system includes a set of coaxial cable to couple the RF signals to and from a base station in which at least one set of the transmitter and receiver is transmitting and receiving said RF signals, two mutually isolated amplifiers, two dividers, at least one combiner, and at least one built-in antenna to couple with a subscriber unit(s). A printed circuit board is provided to assemble said built-in antenna on one side of said printed circuit board, and to assemble other electronic circuits on another side of said printed circuit board, and said printed circuit board is housed a plastic case. Said distributed antenna provides a small sized and very cheap antenna solution to spread RF signals to serve a wider serving area.

Abstract: A duplex RF repeater for use in a personal communications system distributes and enhances time division duplexed signals at a single RF carrier. The duplex RF repeater includes an up-link amplifier and a down-link amplifier which amplify the time division duplexed signals at the single RF carrier. The repeater also includes a down-stream antenna, which links the repeater with a subscriber, and a controller which decreases the gain of one of the up-link or the down-link amplifiers when an RF signal is present at the other of the up-link or the down-link amplifiers to prevent self-oscillation caused by over coupling between the two amplifiers.