EP0499735A2
Expired / Lapsed
EP
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Audio routing within trunked radio frequency multisite switch
Assignee: Ericsson Inc
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Filing: 1991-08-14
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Granted: —
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Expires: 2011-08-14
Abstract
Abstract A distributed trunked radio frequency (RF) switching network (switch) distributes audio routing control and processing throughout the switch, thus avoiding a centralized mixing matrix, increasing fault tolerance and providing low routing request latency time. Each audio source (e.g., RF repeater transmitter, dispatch console microphone) is preassigned an audio channel on a time division multiplexed (TDM) digitized audio network or bus. The audio sources continually broadcast digitized audio signals to all other nodes over the TDM network. Audio routing is performed at the audio destinations (e.g., nodes associated with RF repeater receivers, dispatch console speakers) by selectively "listening" to active TDM network channels. In the preferred embodiment, audio is routed unidirectionally on an "as needed" basis (e.g., in response to radio transceiver "keys" and "unkeys"), and audio routing pathways may change dynamically during an on-going call.
Inventors
- 👤 Philip C. Gulliford
- 👤 Wim A. Imron
- 👤 James L. Teel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 17:22
CPC Classifications
H; H04; H04W; H04W84/00; H04W84/02; H04W84/04; H04W84/08; H04W4/00; H04W4/06; H04W4/10; H04W76/00; H04W76/40; H04W76/45
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
101 words
In a digitally trunked radio frequency communications system, a distributed audio routing arrangement for routing audio signals between plural audio sources and plural audio destinations, said distributed audio routing arrangement comprising: an audio bus; broadcast means, coupled to said plural audio sources, for continually broadcasting audio signals from each of said audio sources over said audio bus; and plural audio routing means, coupled between said audio bus and said plural audio destinations, said plural audio routing means operating in a distributed manner to select audio signals broadcasted over said audio bus and to provide such selected signals to associated audio destinations.
Claim 2
Dependent Claim
18 words
An arrangement as in claim 1 wherein said audio bus comprises a time-division multiplexed digitized audio signal bus.
Claim 3
Dependent Claim
26 words
An arrangement as in claim 1 wherein said plural audio routing means each include mixing means for mixing plural audio signals carried by said audio bus.
Claim 4
Dependent Claim
41 words
An arrangement as in claim 1 wherein said plural audio routing means each include a lookup table storing weighting factors, said audio routing means selecting signals carried by said audio bus in response to weighting factors stored in said lookup table.
Claim 5
Independent Claim
84 words
A method for routing audio signals within a digitally trunked radio frequency communications system of the type having plural audio sources and plural audio destinations, said method comprising the following steps: (a) continually broadcasting audio signals from each of said plural audio sources over a multi-channel audio bus; (b) selecting, in a distributed manner at each of said audio destinations, a subset of said audio signals broadcast over said audio bus; and (c) providing said selected subsets of audio signals to corresponding audio destinations.
Claim 6
Dependent Claim
136 words
A distributed audio routing arrangement for use in a digitally trunked radio frequency communications system of the type having an audio bus carrying plural channels of digitized audio, said audio bus being coupled to plural audio destinations, said audio routing arrangement including for each said plural audio destinations: bus receiving means coupled to said audio bus for receiving digitized audio signals from each of said plural audio channels; a lookup table providing values corresponding to said plural audio channels; summing means, coupled to said bus receiving means and to said lookup table, for selecting a subset of said audio channels in response to the contents of said lookup table and for summing said selected subset of audio channels together; and means for outputting said sum for transmission as an audio signal over a radio frequency link.
Claim 7
Dependent Claim
129 words
In a digitally trunked radio frequency communications system of the type including plural radio frequency repeater sites having corresponding coverage areas and serving mobile/portable digitally trunked radio transceivers disposed within said coverage areas, said system supporting a trunked radio frequency call that includes first and further mobile/portable radio transceiver transmissions, a distributed dynamic audio routing arrangement for routing audio signals comprising: means for establishing a first unidirectional audio routing pathway between said plural radio repeater sites in response to detecting a first mobile/portable transceiver transmission; and means for establishing a further unidirectional audio routing pathway different from said first pathway between said plural radio repeater sites in response to detecting a further mobile/portable transceiver transmission, said first and further transmissions being part of the same bidirectional radio frequency call.
Claim 8
Dependent Claim
153 words
In a digitally trunked radio frequency communications system of the type including plural radio frequency repeater sites having corresponding coverage areas and serving mobile/portable digitally trunked radio transceivers disposed within said coverage areas, said system supporting a trunked radio frequency call that includes plural mobile/portable radio transceiver transmissions, a method of dynamically routing audio signals between said plural sites, said method comprising: (a) detecting transmission of a first mobile/portable radio transceiver; (b) establishing a first unidirectional audio routing pathway between said plural radio repeater sites in response to said detected first transceiver transmission; (c) detecting transmission of a further mobile/portable radio transceiver, said further transceiver transmission responding to said first transceiver transmission and being part of the same call as said first transceiver transmission; and (d) establishing a further unidirectional audio routing pathway different from said first pathway between said plural radio repeater sites in response to said detected further mobile/portable transceiver transmission.
Claim 9
Dependent Claim
31 words
A method as in claim 8 further including the following steps: detecting termination of said first transceiver transmission; and disconnecting said first audio routing pathway in response to said detected termination.
Claim 10
Dependent Claim
93 words
In a digitally trunked radio frequency communications system distributed multisite switching network of the type coupled to plural audio sources/destinations, a distributed audio signal routing arrangement comprising: an audio bus; an audio processor coupled to a first of said audio sources/destinations, said audio processor continually broadcasting audio signals provided by said first audio source/destination over said audio bus, said audio processor including destination circuitry coupled to said audio bus, said destination circuitry selecting a subset of audio signals broadcasted over said audio bus and providing said selected subset to said first audio source/destination.
References Cited (Backward Citations)
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