Arrangement for the waveguide-free bidirectional light or infrared transmission of electrical signals
First Claim
1. A simultaneous, bidirectional waveguide-free optical communication system comprising a plurality of optical transceivers, each transceiver comprising:
- frequency oscillator means for frequency modulating a first information signal onto a subcarrier signal having a particular mean frequency to produce a first frequency modulated signal,emission means for emitting an optical signal corresponding to said first frequency modulated signal produced by said frequency oscillator means,detector means for, simultaneously with emission of said optical signal by said emission means, receiving at least one other optical signal including a second frequency modulated signal from another second optical transceiver,mixing means for mixing said first frequency modulated signal produced by said frequency oscillator means and said optical signals received by said detector means to produce an intermediate frequency signal,frequency demodulation means responsive to said intermediate frequency signal output by said mixing means and said first information signal, for recovering a second information signal from said intermediate frequency signal.
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Abstract
A waveguide-free, simultaneous, bidirectional optical transmission system is disclosed. Each device includes one oscillator for generating a frequency modulated signal. This frequency modulated signal is used for both transmitting a local information signal and for mixing a received modulated signal to produce an intermediate frequency signal of a fixed constant sum frequency. Each device has an FM discriminator for demodulating the intermediate frequency signal to produce a base band signal. Finally, a subtractor is supplied to each device for subtracting the local information signal from the base band signal to recover the received information signal.
9 Citations
12 Claims
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1. A simultaneous, bidirectional waveguide-free optical communication system comprising a plurality of optical transceivers, each transceiver comprising:
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frequency oscillator means for frequency modulating a first information signal onto a subcarrier signal having a particular mean frequency to produce a first frequency modulated signal, emission means for emitting an optical signal corresponding to said first frequency modulated signal produced by said frequency oscillator means, detector means for, simultaneously with emission of said optical signal by said emission means, receiving at least one other optical signal including a second frequency modulated signal from another second optical transceiver, mixing means for mixing said first frequency modulated signal produced by said frequency oscillator means and said optical signals received by said detector means to produce an intermediate frequency signal, frequency demodulation means responsive to said intermediate frequency signal output by said mixing means and said first information signal, for recovering a second information signal from said intermediate frequency signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification