In a predetection combining diversity receiver approximate cophasing of the individual receptions is temporarily achieved by frequency division of the received signals. These signals, which contain independent phase angles so that any two may be randomly out-of-phase, are each applied to identical frequency division circuits. By dividing each carrier frequency by the factor, N, common to all of the dividing circuits, all of the signals will be initially phased within .+-. .pi./N radians. In time...

A data diversity combining technique for a system for data transmission of locks of data each made up of a combination of M distinct and mutually exclusive types of signal elements occurring at a fixed rate, characterized in that an error indication signal is produced during any data signaling element interval during which the detection circuitry is incapable owing to noise, fading or other signal perturbation, to determine which of the M types of signal elements is present during the signaling ...

A communication system utilizing a plurality of receiving antenna which receive digital signals and process all of the received signals in the same trellis type decoder. Hamming weights are applied to each of the signals in accordance with the Viterbi algorithm with only the minimum Hamming weight for any one state transition path between any two levels in the trellis being retained. At the intersection of any two paths in the trellis, the path with the minimum Hamming weight is retained and the...

This invention refers to a diversity antenna system for use in a motor vehicle with at least two diversity antennas as well as a window-mounted heater structure consisting of lateral conductors (bus bars) supplying the heater current and heater sections in between. The configuration is such that each diversity antenna has lateral bus bars (4a, 4d; 4b, 4c) and heater sections (2a, 2b) between them as well as a pair of terminals connected to a feeder network (8a, 8b) of the diversity antenna. Each...

1. A frequency diversity radar system comprising a source of pulses of rering frequency, a source of relatively high power radio-frequency energy periodically energized into oscillations by said recurring pulses and adapted to be voltage tuned over a relatively wide range of frequencies, an antenna responsive to the output of said pulsed oscillations, a source of relatively low power continuous-wave radio-frequency energy adapted to be voltage tuned over said range of frequencies, means responsi...

An FM receiver includes a first antenna and a second antenna. A first pulse generator produces a first pulse according to a noise signal included in the signal received by the first antennas, and a second pulse generator produces a second pulse according to a noise signal included in the signal received by the second antennas. A calculation circuit including shift registers is provided for shifting data, which is either one of the first and second pulses, in one direction in accordance with the ...

A circuit arrangement in a data transmission system for selecting a diversity channel is described. The transmitted information and parity bits are applied in the receiver, over a channel switch and a code frame switch in serial fashion, to a parity bit register and an information bit register. Inputs to a first parity stage are connected to outputs of a number of cells of a first part of the parity bit register and to n1 cells of a first part of the information bit register. A code frame switch...

In a diversity transmission system the problem arises that almost no improvement can be obtained when the signals to be received show frequency selective fading within the band width of the signal to be transmitted. To solve this problem the signal to be received is separated by filter banks into a number of sub-band signals. Corresponding sub-band signals of different filter banks are combined by the combiners into combined sub-band signals. These combined sub-band signals are combined to a bro...

In a communication system, two multi-beam antennas laterally spaced from each other each provide coverage of an azimuth sector for receiving signals from a system user. Each antenna provides lower gain performance at regions of crossover between its beams, as compared to peak gain along the center line of each beam. By aligning the two multi-beam antennas at different azimuths within the sector of interest, angular diversity is achieved. With the peak gain beam center lines of one multi-beam ant...

A reception diversity control method for receiving and demodulating receive signal by multiple receiver circuits, selecting demodulated data received by a receiver circuit in the best reception state from digital demodulated data obtained, the method having the steps of: taking out voice existence information included in the demodulated data selected; and turning on the power sources of all the multiple receiver circuits when the voice existence information indicates that voice information exist...