Abstract: For the purpose of channel state estimation at the receiver end, a reference signal (f.sub.q (t)) is added to and is transmitted with the data signal (f.sub.i (t)) containing the actual information. The addition of the reference signal (f.sub.q (t)) to the data signal (f.sub.i (t)) is effected by means of a quadrature modulation with the reference signal on the Q-axis and with the data signal on the I-axis, the envelopes being selected so that the magnitude of the complex envelope is constant. The receiver has a function stage for preprocessing the receive signal, for quadrature detection of the data signal elements and reference signal elements (y.sub.i) and (b.sub.i) respectively, for selection of the data/reference signal and for estimating the channel state.

Abstract: The receiver contains a correlator (TIC) for the correlation of the received signal with a reference code (R(k)) and a digital signal processor for evaluating the results of the correlation. The correlator is constructed as digital, time-integrating, multistage correlator (TIC), the individual stages (Kl to KN) of which are connected on the one hand to a digital delay line (17) fed with the reference code (R(k)) and to which on the other hand a digital signal (S(k)) recovered from the received signal is applied, to length (D) of the delay line (17) being adapted to the maximum expected impulse response to the transmission channel.

Abstract: A Lithium Tantalate crystal, defined by the Euler angles lambda (.lambda.) equal to about 0.degree. and mu (.mu.) equal to about 90.degree. with an acoustic wave propagation direction angle theta (.theta.) in the range of plus 130.degree. to plus 150.degree. and preferably equal to about plus 141.25.degree., offers unique properties for surface acoustic wave device applications.

Abstract: A base station (BS) and mobile user stations (MS) each with a transmitter (S), a receiver (E) for multipath reception and a control unit (ST) are provided in each cell. Exactly one set of several sequence sets of the auxiliary function used for spectrum spreading is allocated to each cell. Sequences of several sets in pairs have the property that the absolute values of the normalized periodic cross-correlation functions are much smaller than one and for sequences within a set the cross-correlation function in pairs is optimally small around the zero point. Data synchronous generation of the transmission signals takes place in the base station (BS) for all simultaneous connections and the data clock of the received signal is used as data clock of the transmission signal of the user station (MS).Application for digital data transmission in buildings and local areas for the configuration of a so called cordless LAN are considered.