A common baseband digital signal is applied to a plurality of frequency modulators generating frequency modulated signals the carrier frequencies of which are equal to that of a common reference frequency oscillator, and the peak frequency deviations of the frequency modulated signals are made slightly different from each other.

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...

A diversity receiver includes first and second antennae for receiving an RF signal, and an antenna switching circuit for selecting one of the first and second antennae. A first detection circuit having a high sensitivity, and a second detection circuit having a low sensitivity are provided, each detecting a noise signal contained within the received RF signal in different sensitivity. A field strength detection circuit is provided for detecting a field strength of the received RF signal, and a s...

A diversity system utilizing a plurality of branches has been found for an angle modulated digital signal transmission. The received signal on each branch is modulated with a local signal which has the same period as the digital signal, and satisfies the orthogonal relationship with each other. The modulated signals are combined by simply summing them, and the combined signal is differentially detected. In the case of two branches, said orthogonal local signals are .sqroot.2/T.multidot. sin (2.p...

A diversity receiver which comprises two pairs of antennas and tuners and a comparator for comparing two signals obtained from said two tuners so that one of the tuners is selected in response to the result obtained in the comparator includes an antenna switching circuit and an operating antenna indicating circuit which are connected to the comparator so that the antenna associated with the selected tuner by the operation of the antenna switching circuit is indicated in the operating antenna ind...

Diversity combiners for use in satellite and other communication systems. Such combiners are able to accommodate fast and dramatic signal fades and doppler shifts inherent in satellite communications by employing differential and common mode automatic phase control and differential and common mode signal weighting techniques. Phase control takes place in these combiners after signal weighting to decrease differential loop phase detector gradients and noise bandwidth as a function of signal-to-no...

A diversity receiver includes first and second receivers, a first switch, a comparator, a second switch, and a controller. The first and second receiver have receiver antennas and generate demodulated signals and electric field detection outputs in accordance with received electric fields, respectively. The first switch performs switching between the demodulated signals from the first and second receivers in accordance with an output switching control signal and outputs a selected demodulated si...

The diversity receiver having a plurality of antennas and one receiver comprises a detector means to detect a signal voltage responsive to an antenna output from an intermediate frequency amplifier of the receiver, and a comparator unit to receive two separated components of the signal voltage from the detector unit through two separated paths, so that one of the antennas which is in the best receiving condition is selected in response to an output from the comparator unit.

The diversity receiver including plural antennas and one receiver comprises a detector means to detect a signal voltage responsive to an antenna output from an IF amplifier of the receiver and a comparator which is supplied with the signal voltage separated in two courses, one including a fixed bias applying circuit and the other including a time constant circuit, so as to select one of the antennas which is in a good receiving condition.

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 aggre...