A diversity receiver provides plural antennas, one receiving part for receiving the radio wave from one of the plural antennas and a control part for selecting one antenna from the plural antennas, wherein the antenna is selected in a manner that an antenna receiving the most intensive radio wave is detected by switching of the plural antennas in-turn in a time period T.sub.1, and the detected antenna is selected for receiving an information of the radio wave in a time period T.sub.2, the plural antennas may be disposed with distances shorter than a wavelength of the radio wave.
A vehicle tire pressure monitoring system includes a pressure sensor, a transmitter, and a transmitting antenna at each of N wheels of the vehicle, and at least one receiving antenna attached to the vehicle, respectively allocated to each transmitting, antenna. The receiving, antenna is connected to an electronic receiving, and analysis system which determines whether a signal belongs to the local vehicle by allocating an identifier characterizing the individual wheel to its transmitter. Emitted signals contain the identifier and are forwarded to the central electronic receiving and analysis system, which records the signal intensities under the signal's identifier, compares the intensities, selects those N transmitter identifiers with the greatest intensities, then stores the N transmitter identifiers as belonging to the vehicle.
A radio receiver system for receiving double sideband signals from a plurality of antennas (N1,N2) having different reception characteristics detects a reduction in power in one of the sidebands of a received signal, due to multiple path reception or other disturbances. The system then selects for use by the receiver a signal from an antenna less affected by the disturbances.
An antenna selecting diversity receiving apparatus utilizes linear modulation with information about the envelope of a modulating wave included therein and is employed in a radio communication system using TDM. An integrating circuit serves to integrate electric-field levels received by respective antennas over a predetermined period of time before a start in a time slot allotted to a radio receiver. Then, a comparing circuit makes a comparison among respective time-integrated values corresponding to the respective antennas. In addition, a changeover control circuit serves to select an antenna corresponding to the maximum time-integrated value as the antenna used during the period of the time slot allotted to the radio receiver.
A digital camera having a wideband RF transceiver, includes: a graphic user interface for displaying a camera control menu, the graphic user interface having a normal viewing axis; camera grips located on opposite sides of the camera body for holding the camera to operate the transceiver while viewing the graphic user interface; and a directional antenna arranged with respect to the camera to point away from a user of the camera and having a 90.+-.10 degree vertical beam width centered on the horizon .+-.20 degrees, and a 180.+-.20 degree horizontal beam width when the camera is held by the grips for normal viewing of the graphic user interface while operating the transceiver.
A diversity combiner is provided for combining two received radio signals having the same frequency and modulation. For each of the radio signals (s, s') there is included a mixer (1, 1') with an associated voltage controlled local oscillator (2, 2') and a following intermediate frequency filter (3, 3') for generating an intermediate frequency signal (m,m') and a phase comparator (5, 5') for comparing the intermediate frequency signal with a reference signal (a) originating from a weighted aggregate (e) of the intermediate frequency signals (m, m). Each phase comparator (5, 5') sends a signal responsive to the phase difference and which controls the frequency of the local oscillator (2, 2'). The weights of the sub signals can be varied such that the quotient of the contribution of the sub-signals to the aggregate can be caused to correspond to an arbitrary power, which is greater than or equal to one, of a corresponding quotient before the addition. This is achieved by the aggregate being formed by a signal weighting and adding circuit (8), which includes four bipolar transistors, and which is controlled by two voltages (N, N') which are responsive to the logarithm of the amplitude of the intermediate frequency signals (m, m').