Es wird eine Sende-Empfangs-Diversity-Anlage vorgeschlagen, die aus einer Zentraleinheit (10), mehreren ortsfesten Sende-Empfangsstationen (11,11') und einer Vielzahl von Mobilstationen besteht. Dabei wird erfindungsgemas in jeder Sende-Empfangsstation (11,11') ein dem Signal/ Rauschverhaltnis entsprechendes Bewertungssignal gebildet und dieses zur Zentrale (10) ubertragen. In der Zentrale (10) werden die Bewertungssignale der einzelnen Stationen (11,11') mit einem fur jede Station getrennt einstellbaren vorgegebenen Wert verglichen und der Signalweg durchgeschaltet, dessen Signal die beste Qualitat aufweist.

Sende-Empfangs-Diversity-Anlage

Automatic receiver selecting arrangement for central radio stations in which communication signals are simultaneously received via several radio receiving stations set up at various sites and are transmitted via post-office lines or other communication paths with a transmission frequency range of 300 to 3400 Hz to the central radio station. To each receiving path (E1...n), a noise weighting circuit (Stb1...n) is allocated in the central radio station, which circuit weights the communication signals in accordance with their frequency components within the transmitted range from 300 to 3400 Hz and converts them into a direct voltage which depends to a small extent on the useful signal and to a high extent on the noise components. The direct voltages are continuously compared (EWA) and control switches (S1...n) for switching the best receiving paths through to a listening station (L).

Automatic receiver selecting arrangement for central radio stations.

1 Voice and data transmission system having a central transmitting and receiving station (10), a plurality of spatially distributed, staggered radio transmitting and receiving stations (16  20) each connected to the central transmitting and receiving stations by way of a respective signal path (11  15), mobile radio transmitting and receiving stations (27  32) associated with the staggered radio transmitting and receiving stations and a diversity selecting device (40) which forms part of the central transmitting and receiving station and which, by automatic, sequential interrogation of the individual signal paths, in each case establishes that signal path which is supplying the transmitted speech and data signals of the best possible quality and switches this signal path to an operator's unit (50) of the central transmitting and receiving station, characterized in that the diversity selecting device (40) has an associated data evaluator (43) which, when it detects in the voice and data signals a starting signal characterising the commencement of the data transmission, produces a blocking signal, which holds the opened signal path, until the data evaluator detects a stop signal characterising the end of a data transmission

Voice and data transmission system

Empfaengerauswahlautomatik fuer Funkzentralen

The evaluator allows route selection to occur both in terms of the path the communications travel to the central station and in terms of the signal-to-noise ratio of any path, i.e. the path with the largest signal to noise ratio is selected. The amplitude of the signal in each path is compared with the noise in that path to produce a difference voltage for each path. The difference voltages from different paths are compared one with another and the path having the largest difference voltage is selected for transmitting the wanted signal.

Gerd Wagner

Papers

Evaluator for radio communications centres - decides signal route by choosing path with largest difference between signal and noise