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EP0368549A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Multiplexed fibre optic system with auxiliary channel

Assignee: STC PLC
•
Filing: 1989-11-01
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Granted: —
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Expires: 2009-11-01
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Abstract

Abstract A digital data transmission system wherein digital data channels are serially multiplexed and in which channel identification is encoded by displacements of zero crossings of the multiplexed data. The multiplexed data stream is differentially encoded so that data bits of one significance are represented by the presence of transitions in the transmitted signal at predetermined times and data bits of another significance are represented by the absence of transitions at said predetermined times. The differentially encoded signals are added to a clock at half the interleaved bit frequency so that the rising and falling edges of the bits are advanced and retarded according to their bit position. The multiplexed data with added clock is then high-pass filtered and linearly added to band limited auxiliary data before transmission.

Inventors

  • 👤 William Hugh Powell

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 02:16
CPC Classifications
H; H04; H04L; H04L7/00; H04L7/0054; H04L7/0066; H04J; H04J3/00; H04J3/16; H04J3/1605; H04L7/0008

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 55 words
According to one aspect of the present invention there is provided a digital data transmission system characterised in that digital data channels are serially multiplexed and framing and clock information is impressed on the digital data stream by displacement of zero crossings according to a predetermined rule based on bit position in the data stream.
Claim 2
Dependent Claim 55 words
According to one aspect of the present invention there is provided a digital data transmission system characterised in that digital data channels are serially multiplexed and framing and clock information is impressed on the digital data stream by displacement of zero crossings according to a predetermined rule based on bit position in the data stream.
Claim 3
Dependent Claim 25 words
A system according to claim 1 characterised in that the predetermined rule is based on both bit position and data values in the data stream.
Claim 4
Dependent Claim 28 words
A digital data transmission system characterised in that two digital data channels are serially multiplexed and in which the odd and even numbered time-slots have respectively different durations.
Claim 5
Dependent Claim 28 words
A digital data transmission system characterised in that two digital data channels are serially multiplexed and in which the odd and even numbered time-slots have respectively different durations.
Claim 6
Dependent Claim 80 words
A system according to claim 3 characterised in that the digital data streams to be multiplexed are encoded by respective one-bit analogue-to-digital converters the outputs of which are interleaved to form the serially multiplexed channels, the multiplexed data stream is differentially encoded so that data bits of one significance are represented by the presence of transitions in the transmitted signal at predetermined times and data bits of another significance are represented by the absence of transitions at said predetermined times.
Claim 7
Dependent Claim 33 words
A system according to claim 3 characterised in that the differentially encoded signals are added linearly to an auxiliary data stream of lower bandwidth than the bandwidth of the channels which are multiplexed.
Claim 8
Dependent Claim 19 words
A system according to claim 4 or 5 characterised in that one bit analogue-to-digital converters are sigma-delta A/D converters.
Claim 9
Dependent Claim 31 words
A system according to claim 4, 5 or 6 characterised in that the differentially encoded signals are added linearly to a clock signal at half the frequency of the interleaved bits.

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