Communicating or reproducing an audible sound
First Claim
1. A method of optically communicating an audible sound along an optical link, the method comprising:
- transmitting, onto the optical link, pairs of optical signal copies, the optical signal copies of a given pair having a time offset relative to one another of at least 75 microseconds;
phase modulating the transmitted optical signal copies on the optical link, the phase modulation being caused by audible sound waves propagating through air to impinge on a sensing portion of the optical link;
receiving reflected modulated optical signal copies previously transmitted onto the optical link; and
,for received pairs of optical signal copies, causing one optical signal copy of a pair to mix with the other optical signal copy of that pair so as to produce a signal representative of a sensed audible sound.
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Accused Products
Abstract
The present invention relates to the communication or reproduction of sound, in particular audible sound. There is provided a method of communicating a sound, including the steps of: transmitting, onto an optical link, pairs of signal copies, the signal copies of a given pair having a time offset relative to one another; applying the audible sound to the optical link, such that the audible sound causes a phase modulation to the transmitted signal copies; receiving modulated signal copies previously transmitted onto the link; and, for received pairs of signal copies, causing one signal copy of a pair to mix with the other signal copy of that pair so as to produce a signal representative of the sound. The sound is an audible sound. It has been found that a delay of at least 75 micro seconds allows for a better reproduction of audio sounds, since these have a relatively low frequency content.
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Citations
9 Claims
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1. A method of optically communicating an audible sound along an optical link, the method comprising:
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transmitting, onto the optical link, pairs of optical signal copies, the optical signal copies of a given pair having a time offset relative to one another of at least 75 microseconds; phase modulating the transmitted optical signal copies on the optical link, the phase modulation being caused by audible sound waves propagating through air to impinge on a sensing portion of the optical link; receiving reflected modulated optical signal copies previously transmitted onto the optical link; and
,for received pairs of optical signal copies, causing one optical signal copy of a pair to mix with the other optical signal copy of that pair so as to produce a signal representative of a sensed audible sound. - View Dependent Claims (2, 3, 4, 7)
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- 5. A method as claimed in 1, wherein the temporal offset is achieved using interferometer means.
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8. A microphone system for reproducing an audible sound, comprising:
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an optical link for sensing the audible sound; a transmission stage for transmitting, onto the optical link, pairs of optical signal copies such that the signal copies of a given pair have a time offset relative to one another of at least about 75 microseconds; and
,a receiving stage for receiving reflected optical signals of the optical signal copies previously transmitted onto the link, wherein; the optical link is arranged such that audible sound waves propagating over air and impinging on a sensing portion of the optical link cause the optical signal copies to suffer a phase modulation; and the receiving stage is arranged, for received reflected pairs of optical signal copies, to cause one optical signal copy of a pair to mix with the other optical signal copy of that pair so as to enable reproduction of a sensed audible sound in the form of a sound signal. - View Dependent Claims (9)
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Specification