In a space diversity reception system, a plurality of receiving circuits, each of which is connected to respective antenna, outputs a first type signal having a level which varies in accordance with the radio frequency signal level input to the receiving circuit. An automatic gain-controlled amplifier amplifies the first type signal so as to output a second type signal having a substantially constant level. A phase control circuit detects a phase difference between the second type signal output ...

In a space diversity receiver, multiple signal paths are connected respectively to antennas for multipath reception. Each signal path includes a digital demodulator coupled to the antenna and an impulse response detector, or autocorrelator connected to the demodulator for deriving a channel impulse response of each one of the multiple paths. A maximum response detector is connected to each impulse response detector for detecting equalizable delay components which give a maximum response value an...

The disclosure relates to methods and apparatus for combining a multiplicity of diversely received replicas of a signal originating in the same remote transmitter. The disclosed methods and apparatus apply, in particular, to digitally modulated sinusoidal prime-carriers or subcarriers, and base the final decision about which of the code alphabet symbols is present in each bit-symbol time slot on either: a) the maximum value of a decision index for each code alphabet letter indicated in/for the s...

A diversity control circuit which selects an optimum receiving signal in a diversity receiver and which corrects receiving signal levels in such a manner that characteristics in measuring systems for a plurality of receiving signal levels can be regarded as homogeneous. The circuit includes memory means which stores correction data and which responds to receiving signal levels to provide corrected signals conforming to a preselected characteristic.

A diversity antenna communication system for mounting on and use with a mobile body. The system includes at least two receiving systems having different propagation paths from one another. During the transmission, a radio wave including receiving system change-over timing signals therein is radiated. Upon reception, the change-over timing signals are extracted to control reception.

A new system and technique for cancelling interference in frequency agile ceiving systems. Main and auxiliary signals are supplied to a pair of multiple loop side-lobe cancellers which are capable of being tuned to different frequencies. At the same time, under the control of a timing clock, plural frequencies are selected and multiplexed between two channels at the time of a radar pulse transmission. The side-lobe cancellers and radar are coupled to the channels such that each caneller operates...

A diversity receiving apparatus having a plurality of antennas, antenna feeders each being associated with respective one of the antennas, and a single diversity receiving section to which the antennas are connected via the associated antenna feeders. A breakage detecting circuit is included in the apparatus for detecting the breakage of any one of the antenna feeders. The detecting circuit uses an antenna whose radiation element is connected to ground and, by applying a predetermined DC potenti...

A diversity control circuit which selects an optimum receiving signal in a diversity receiver and which corrects receiving signal levels in such a manner that characteristics in measuring systems for a plurality of receiving signal levels can be regarded as homogeneous. The circuit includes memory means which stores correction data and which responds to receiving signal levels to provide corrected signals conforming to a preselected characteristic.

An adaptive polarization diversity system for radio link communication. The system includes a base station antenna for transmitting either a clockwise polarized transmission or a counterclockwise polarized transmission, the transmission including a training pilot signal. The system further includes at least one subscriber unit for receiving the transmission, the unit including a first subscriber unit antenna for receiving a clockwise polarized transmission, a second subscriber unit antenna for r...

After coding transmission data by means of an error-correction coder, the data are divided into N branches, pass through a plurality of delay elements, undergo interleaving in an interleave circuit, primary modulation in a modulator, undergo spread-spectrum processing in a spread-spectrum circuit, and are coded/multiplexed in a synthesizer, and finally transmitted. The signals transmitted by the transmitter are divided into N branches by a branch circuit, undergo inverse spread-spectrum processi...