Siemens Aktiengesellschaft

Theodor Schwierz

Martin C Mueller

Erich Burger

Bernd Sommer

Wolfram Schwarz

A method for the recovery of a plesiochronic data signal is provided, whereby the received sum signal generated upon application of what is referred to as pulse stuffing is divided into a synchronous data signal and into an additional data signal in a demultiplexer. A data bit likewise transmitted in the additional data signal is inserted into the synchronous data signal in a format converter on the basis of stuffing information transmitted in the additional data signal or, respectively, a bit is purged from the synchronous data signal. The stuffing information is composed exclusively of phase words which, in digital form, contain the momentary phase relationship between the sum signal and the plesiochronis data signal. A command evaluation stage forwards control signals to the format converter when the extreme values of the phase words are transgressed, the bits being inserted into the synchronous data signal or, respectively, purged from the synchronous data signal by way of the control signals.

Demultiplexer of a digital signal transmission apparatus

A method of frame decoding a series data flow having a frame structure containing an item of periodically occurring synchronizing information, employs a frame recognition circuit, which is synchronized to the item of synchronizing information and is coupled to a frame generator. After a predetermined number of synchronous coincidences of the item of synchronizing information and a synchronizing signal emitted from the frame generator, the frame recognition circuit and frame generator are decoupled. During synchronous coincidence, a weighting counter is periodically increased by a predetermined amount, and in the case of non-coincidence it is periodically reduced by a predetermined amount. Resynchronization takes place only when the count of the weighting counter has reached its maximum value and the frame recognition circuit is synchronized to a new item of synchronizing information.

Frame decoding

In a method of transmitting digital signals using so-called pulse stuffing, in which plesiochronous (nearly-synchronous) data signals are transmitted in a main channel of a sum signal channel as synchronous data and in an auxiliary channel of a sum signal channel as additionl data together with stuffing data, it is proposed that the stuffing data should consist of phase words which contain, in digital form, the phase relationship between the sum signal and the plesiochronous data signals.

Method and apparatus of transmission for a digital signal

Frequency diversity is employed to counter selective fadings as a result of multi-path propagation for troposcatter and short-wave connections for digital useful signals employing frequency modulation. For this purpose, the digital useful signal is supported on a frequency arrangement comprising at least three radio frequencies in that the digital useful signal, together with at least one additional oscillation, and, in fact, an additional fundamental oscillation which determines the frequency of the spacing in radio-frequency frequency arrangement, is fed to the input of a frequency modulator. At the input end, the radio-frequency carriers of the frequency arrangement, which are each modulated with the useful signal, are all converted by coherent mixing into the same frequency level, from which, by way of a combiner, a sum signal is obtained which is the optimum in respect of signal-to-noise ratio.

Digital radio system

A directional antenna system with electronically controllable sweep of the beam comprising a radiator arrangement facing toward a reflector and including a switching and control apparatus connected to the radiator and in which very rapid sweeps of the beam direction can be accomplished with high precision and utilizing a large plurality of individual radiators arranged in a matrix with rows and columns and wherein the control and switching apparatus selectively actuates particular ones of the individual radiators such that switching between different groups of radiators causes a change in the beam direction due to the spatial change in position relative to the primary radiator.

Directional antenna system with electronically controllable sweep of the

The invention relates to a measuring installation for a frequency analysis of signal levels within a large volume range which is to be extremely fast. The measuring installation has an intermediate frequency amplifier arrangement with two and more selective amplifiers (SV1, SV2, SC3) which are equipped in each case with an automatic amplification regulation. The loop is broad band and contains a controllable attenuator (PR1, PR2, PR3) and a variable-gain amplifier (RV1, RV2, RV3). The band width of the selective amplifiers connected in series is reduced step-by-step in the direction of the signal flow. The regulating variables of the variable-gain amplifiers are summed in an adder (Ad) and supplied to a signal level evaluation and display installation (AA).

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Klingen, Germany

Theodor Schwierz