US 5,204,979 AGranted

Diversity receiving method and apparatus for combining a plurality of rapidly changing signals

AssigneeRichard Hirschmann GmbH & Co.

InventorsDieter Schenkyr, Walter Buck

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Abstract

According to the receiving method for mobile reception has a plurality of individual receiving antennas, also known as diversity receiving method, on the individual antenna output signals an auxiliary modulation is superimposed and the antenna output signals are added to give a summation signal which as amplified selected intermediate-frequency summation signal is then demodulated in relation to amount and frequency or phase, the phase position of an individual signal in relation to the phase position of the summation signal and/or the amplitude contribution of an individual signal to the amplitude of the summation signal thereby being determined. This information is utilized for optimizing the useful signal with a view to optimum interference suppression for example in that the phases and/or amplitudes of the high-frequency individual signals are changed in dependence upon the phase position and/or amplitude contribution determined. With low circuitry expenditure this then gives a substantially improved reception quality in mobile systems. Receiving antenna systems for carrying out the method are described.

Claims34

Dependent claims

A method for diversity reception of radio signals using at least two receiving antennas where the output signal of each receiving antenna is modulated by an auxiliary modulation signal, phase shifted, combined in a summation circuit, amplified and selected in a radio receiver, coherently demodulated, then used to control the amount of phase shift made to each antenna output signal such that the resultant signal summation is maximized for best reception, comprising the steps of:

modulating each of a plurality of antenna output signals with an auxiliary modulation signal;
phase-shifting each of said modulated antenna output signals so that the phase of each of said output signals are approximately the same;
summing each of said modulated and phase-shifted antenna output signals together, wherein a summation signal is thereby generated;
receiving said summation signal by amplifying and selecting said summation signal in a receiver circuit;
filtering said received summation signal;
demodulating said filtered received summation signal in amplitude and frequency demodulators;
coherently detecting the demodulated signals from said amplitude and frequency demodulators in synchronous demodulators, wherein the output of said amplitude demodulator is coherently detected with said auxiliary modulation signal and the output of said frequency demodulator is coherently detected with said auxiliary modulation signal phase shifted by ninety degrees, whereby the amplitude and phase relationship of each of said antenna output signals is determined and therefrom the phase position and amplitude contribution of each of said antenna output signals in relation to said summation signal is derived;
and
adjusting the phase-shift of each of said antenna output signals by means of the information derived from said synchronous demodulators so that said summation signal is optimized for maximum resulting amplitude and best reception.

6 more elements

Apparatus for diversity reception of radio signals using a plurality of receiving antennas where the signal from each receiving antenna is modulated by an auxiliary modulation signal, phase shifted, combined in a summation circuit, amplified and selected in a radio receiver, coherently demodulated, then used to control the amount of phase shift made to each antenna output signal such that the resultant signal summation is maximized for best reception, comprising:

a plurality of receiving antennas (1-1, 1-2, 1-3, 1-4);
a modulator (3) connected to said receiving antennas (1-1, 1-2, 1-3, 1-4) and modulating each of the signals from said receiving antennas with an auxiliary modulation signal (S.sub.H), wherein each of the modulated signals has an auxiliary modulation component;
a phase setting member (4) connected to said modulator (3) and adapted to phase-shift each of the modulated signals from said modulator (3);
a summation circuit (5) connected to said phase setting member (4) and adapted to sum the modulated and phase-shifted signals from said phase setting member (4) into a summation signal, wherein the summation signal is comprised of the phase shifted antenna signals and auxiliary modulation components thereto;
a receiving circuit (7) connected to said summation circuit (5) and adapted to amplify and select the summation signal therefrom;
a filter (8) connected to the receiving circuit (7) for filtering the auxiliary modulation components from the summation signal;
first and second demodulators (9, 10) connected to said filter (8) and which demodulate auxiliary modulation components in the summation signal;
first and second synchronous demodulators (11, 12) connected to said first and second demodulators, respectively, said synchronous demodulators (11, 12) determining from the auxiliary modulation components, the real and imaginary parts of each of the signals from said receiving antennas (1-1, 1-2, 1-3, 1-4) in relation to the summation signal and derives therefrom the phase position and amplitude contribution of each of the antenna signals to the summation signal;
and
a phase controller connected to said synchronous demodulators (11, 12) and converting the phase position and amplitude contribution for each antenna signal into control signals for controlling said phase setting member (4), whereby the individual antenna signals are phase-shifted so as to optimize the summation signal for maximum amplitude and best reception.

7 more elements

Dependencies are inferred from the claim text.