EP0492862A2
Expired / Lapsed
EP
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Daisy chain multiplexer
Assignee: Raytheon Co
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Filing: 1991-12-05
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Granted: —
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Expires: 2011-12-05
Abstract
Abstract Each unit of a daisy chain of separate and independent multiplexing units (10, 12,14) is arranged to accept a group of local audio inputs (Audio 1 - Audio 8) and an additional input (18, 20, 22) from a prior unit in the chain to time division multiplex the additional input with the local units. Each unit provides a single serial bit stream output (20, 22, 24) which comprises the additional input to the next identical multiplexer unit in the chain. The next multiplexer unit time division multiplexes all of its inputs to provide a single output which includes a serial presentation of its own local inputs and the local inputs of the preceding multiplexer unit of the chain. This single serial output of the next multiplexer then forms the additional input of a still further multiplexer unit of the chain, which itself may have its own local inputs. The third multiplexer unit provides a single output that is a serial presentation of the local inputs of all three multiplexers. Additional multiplexer units can be added to the chain as may be necessary or desirable to accommodate reconfiguration of systems with which the multiplexers are used. For serial presentation of the local inputs of the several multiplexers units, system timing (84) provides a time frame, common to all units, that is subdivided into a number of subframes (subframes 1,2,3), which number is equal to the maximum number of multiplexer units that is expected to be employed in the chain. Each individual multiplexer unit of the chain is assigned a specific one of the subframes which uniquely contains data of its local inputs. For multiplexer units at the beginning of the chain only those subframes at the beginning of a frame may have data, whereas other subframes contain no data. For a final multiplexer in the chain, where the number of multiplexer units is equal to the number of subframes, all subframes contain data, with the data of each subframe being unique to the local inputs of the single individual multiplexer unit corresponding to the particular subframe.
Inventors
- 👤 Kenneth A. Brady, Jr.
- 👤 Richard E. Sklar
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:25
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/16; H04J3/1605; H04J3/1623; H04J3/1647; B; B64; B64D; B64D11/00; B64D11/0015; B64D11/00155; H04J3/02; H04J3/04; H04J3/047
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
133 words
A multiplexer unit comprising: means for providing a first group of inputs, means for providing a second group of inputs, multiplexer timing means for establishing a repetitive time frame subdivided into a plurality of subframes, each said subframe being divided into a plurality of time slots, and means responsive to said first and second groups of inputs and said timing means for time division multiplexing said inputs to provide a composite serial bit stream of data bits, data bits of the inputs of said first group all being uniquely assigned to an individual one of said subframes and data bits of said second group being uniquely assigned to a an individual one of said subframes, at least some of the time slots of one of said subframes being free of any data bits.
Claim 2
Dependent Claim
22 words
The multiplexer of Claim 1 wherein no data bits are assigned to all time slots of at least one of said subframes.
Claim 3
Dependent Claim
60 words
The multiplexer of Claim 1 wherein said repetitive time frame is subdivided into a number of subframes that is greater than the number of said groups of inputs, and wherein the data bits of said groups of inputs are assigned to less than all of said subframes whereby there are no data bits in at least one of said subframes.
Claim 4
Dependent Claim
85 words
The multiplexer of Claim 1 wherein the inputs of said second group are greater in number than the number of time slots in said second subframe and include first and second subgroups, and wherein data bits of the first subgroup of inputs of said second group of inputs are uniquely assigned to time slots of said second subframe and wherein data bits of a second subgroup of said second group of inputs are uniquely assigned to time slots of a third one of said subframes.
Claim 5
Dependent Claim
41 words
The multiplexer of Claim 1 wherein the inputs of said first group of inputs include local analog audio signals, and including converter means for individually converting each of said local analog audio signals to digital samples representing such analog audio signals.
Claim 6
Dependent Claim
56 words
The multiplexer unit of Claim 5 wherein said second group of input signals comprises a group of digitized samples of audio signals modulated upon an RF carrier, means for demodulating said carrier to provide a bit stream of said digitized samples for time division multiplexing with the digitized samples of said first group of input signals.
Claim 7
Dependent Claim
251 words
A chain of multiplexers comprising: first and second multiplexer units, said first multiplexer unit having a plurality of local inputs and an output, said second multiplexer unit having a plurality of second unit local inputs and having a remote input connected to receive the output of said first multiplexer unit, said first multiplexer unit including: timing means for generating frame sync signals establishing a repetitive frame divided into plurality of subframes, means in said first multiplexer unit for time division multiplexing said input signals and assigning all of said input signals to individual time slots in a selected one of said subframes, a second one of said subframes having no signals assigned thereto, said first multiplexer unit having an output including signals of said selected subframe and bearing frame sync signals, said second multiplexer unit including: means for multiplexing said second unit local inputs with the remote input from the output of said first multiplexer unit, second timing means for establishing a second multiplexer timing frame based upon said frame sync signals of said first multiplexer unit output, said second multiplexer timing frame having said plurality of subframes, said second timing means including means for assigning signals contained in the output of said first multiplexer unit to said selected one of said subframes and for assigning said second unit local inputs to said second one of said subframes to provide an output from said second multiplexer unit comprising said first multiplexer unit local inputs followed by said second unit local inputs.
Claim 8
Dependent Claim
20 words
The apparatus of Claim 7 wherein said first and second multiplexer units are positioned at a distance from one another.
Claim 9
Dependent Claim
66 words
The apparatus of Claim 6 including modulator means in said first multiplexer unit for modulating said local input to said first multiplexer unit upon a radio frequency carrier together with frame sync signals,to provide a modulated RF carrier output, said second multiplexer unit including means for demodulating said RF carrier output and deriving frame sync signals therefrom for defining frame and subframes for said second multiplexer.
Claim 10
Independent Claim
219 words
A method for time division multiplexing different groups of input signals comprising the steps of: providing a first group of inputs, time division multiplexing digitized samples of the signals of said first group of inputs in a train of repetitive time frames each divided into a plurality of subframes, each having a plurality of time slots, assigning the digitized samples of said first group of inputs to respective time slots of first individual one of said subframes, transmitting as a remote signal said repetitive time frames and the subframes of each frame with said digitized samples in said first individual subframe, and at least one other subframe having no digitized samples, providing a second group of inputs, establishing a train of repetitive time frames synchronized with said first mentioned train and subdivided into said plurality of subframes and time slots, time division multiplexing said remote signal with said second group of inputs, said last mentioned step of multiplexing comprising: assigning digitized samples of said remote signal to time slots of said first individual one of said subframes, providing digitized samples of a second group of inputs and assigning them to time slots of a second individual one of said subframes, and providing an output signal comprising said time frames with digitized samples in said first and second individual subframes.
Claim 11
Dependent Claim
14 words
The method of Claim 10 wherein said multiplexers are positioned at mutually displaced locations.
Claim 12
Dependent Claim
90 words
The method of Claim 10 wherein said first group of inputs comprises the output of a first signal source located at a first position, and said second group of inputs comprises the output of a second signal source located at a second position displaced from said first position, said step of performing said first mentioned multiplexing being carried out at a location adjacent said first signal source and said step of multiplexing said remote signal being carried out at a position closely adjacent the location of said second audio source.
Claim 13
Dependent Claim
428 words
A daisy chain multiplexing system comprising: a first audio source providing a first group of local analog audio inputs, a first multiplexer unit comprising: a plurality of analog to digital converters each connected to uniquely receive a different one of said local analog audio inputs and to provide digitized samples of said local inputs, an array of multiplexing switches connected to receive said digitized samples and provide a composite stream of said samples, multiplexer timer means for generating frame sync and time slot signals for establishing a repetitive frame divided into at least first and second subframes, each said subframe having a plurality of time slots, said timer means including means for assigning digitized samples of said local inputs to the time slots of said first subframes and for keeping time slots of said second subframe free of digitized samples, means for combining the frame sync and time slot signals with said composite serial bit stream of samples from said multiplexing switches to provide a combined first multiplexer unit output, a second audio source positioned at a location remote from said first audio source and providing a second group of local analog audio inputs, a second multiplexer unit positioned adjacent said second audio source and comprising: a second plurality of analog to digital converters each connected to receive a different one of said second local analog audio inputs, and to provide digitized samples thereof, a second array of multiplexing switches connected to receive said digitized samples from said second plurality analog to digital converters, one of said second group of multiplexing switches being connected to receive said combined first multiplexer unit output, said switches being connected to provide a combined second multiplexer unit output, second multiplexer timer means in said second multiplexer unit responsive to the frame sync and time slot signals of said first combined multiplexer unit output for establishing a repetitive frame and time slots therefor for said second multiplexer, said repetitive frame of said second multiplexer being subdivided into at least first and second subframes, said second timer means including means for uniquely assigning digitized samples of the first group of local audio inputs from said first source to a first one of said subframes and for assigning the digitized samples of the second group of local analog audio inputs to said second subframe to provide said combined second multiplexer unit output including in each frame thereof digitized samples of said first group of audio inputs from said first source followed by digitized samples of said second group of audio inputs from said second source.
Claim 14
Dependent Claim
53 words
The daisy chain multiplexer of Claim 13 including modulator means connected to said first mentioned multiplexing switches for modulating said combined first multiplexer unit output upon an RF carrier to provide an RF carrier output having modulated thereon digitized samples of the local inputs from said first audio source and frame sync signals.
Claim 15
Dependent Claim
56 words
The multiplexer of Claim 14 wherein said second multiplexer unit includes demodulator means for demodulating said RF carrier output and extracting frame sync and time slot signals therefrom, said second timer means being responsive to said frame sync signal for establishing frame synchronization and time slot positions of the composite signal combined second multiplexer unit output.
Claim 16
Dependent Claim
107 words
A multiplexer unit comprising: timing means for generating a train of repetitive time frames each subdivided into a plurality of subframes, each said subframe having a plurality of time slots, means for providing a plurality of input signals to said multiplexing unit, means responsive to said input signals for sequentially positioning each of said input signals in successive time slots of one of said subframes to provide a multiplexer unit output comprising a train of repetitive time frames each having an input signal in successive time slots of a single one of its subframes, and having no signals in time slots of the other of its subframes.
References Cited (Backward Citations)
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