Ant Nachrichtentechnik Gmbh

Robert Boschgmbh

Ericsson Ab

Marconi Communications Gmbh

Volker Hespelt

Thomas Alberty

Khaled Fazel

Franz-Josef Hagmanns

Heike Hofmann

Volker Engels

Waldemar Hauk

Bernd Freidrichs

A method for monitoring a redundant (passive) transmitter, being, for example, part of a base station of a point-to-multipoint radio communications system transmits, during normal operation, a spread-spectrum signal over the redundant transmitter, the spread-spectrum signal being of low spectral power in comparison with data signals being transmitted by the active transmitter of the base station. One or more receivers are associated, for example, with terminal stations in communication with the base station and detect the presence of the spread-spectrum signal. If the spread-spectrum signal is not found to be present, the receivers provide an indication of this, and from this indication, a decision is made as to the integrity of the redundant transmitter.

Method and apparatus for monitoring a redundant (standby) transmitter in a radio communications system

A method of operating a message receiver for a message, that is present as a burst, which includes at least a training sequence and useful data is performed by stepwise synchronizing the receiver with the burst as the burst is received.

Method of operating a message receiver

To calibrate a transmitter and/or sender for controlling a beam forming network, each of the control signals is divided into a plurality of frequency segments. The control signal of each frequency segment is multiplied by complex coefficients so that the transmitter output signals, after passing through a reference receiver, are identical to the respective control signals. A similar adjustment is performed for the receive direction. The method and the device allow the same beam characteristic.

Calibration method and arrangement

A method of synchronizing clock pulses of a clock pulse generator used in a receiver of digital data transmissions. The received signal is demodulated by multiplying it in quadrature by an output signal of a carrier oscillator to obtain demodulated in-phase and quadrature components. The demodulated components are lowpass filtered to suppress harmonics of the carrier frequency and then bandpass filtered into two complex signals. The two complex signals are then linked together with a first linkage circuit to form a first control signal u.sub.TI. The two complex signals are also linked together with a second linkage circuit to form a second control u.sub.TR, wherein the two control signals can be interpretated as the real and imaginary components of a complex control signal u.sub.T =u.sub.TR +ju.sub.TI. The two components are separately averaged and then evaluated to form an actuation signal having an actuation value .delta. representing an error in the timing of the error pulse generator relative to the received signal. The evaluation is based on the relationship .phi.=arc tan u.sub.TI /u.sub.TR, where .phi. is the phase error in the clock pulse relative to the received signal.

Method for clock pulse synchronization

Timing error detector

A method and circuit arrangement for synchronizing a receiver in a digital transmission system with transmission of a special preamble selected in such a manner that, with correct demodulation, the received signal has a cosine shape with a pattern frequency fp from which the clock pulse frequency results, and wherein frequency and/or phase of the carrier and clock pulse signal, respectively, are estimated, and, after demodulation with an assumed carrier frequency ft0, the individual spectral lines (gp, gn) of the received signal (rd) are obtained by filtering, and from these signals, their frequency (fgp, fgn) and phase ( gp, gn) are determined by linear regression, with these frequency and phase values being used, by means of subsequent difference and sum formation, to obtain the following estimated values: ##EQU1##

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Backnang, Germany

Volker Hespelt