Josephson junction FSK demodulator
First Claim
1. A demodulator for detecting a digital signal that is frequency-shift-keyed modulated onto a carrier signal comprising:
- a Josephson junction;
means for applying the modulated carrier signal to said Josephson junction;
means for directly detecting the ONEs and ZEROs of said digital signal from voltage variations generated across said Josephson junction in response to said applied modulated carrier signal.
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Accused Products
Abstract
A Josephson junction (100) is employed as a very-high-speed frequency demodulator for detecting a frequency-shift-keyed (FSK) modulated signal (201) in a microwave or lightwave communication system. The voltage induced across the junction in response to an incident FSK modulated radiation signal follows the frequency variations in the incident wave thereby directly demodulating the information signal from its carrier. In the disclosed embodiment an FSK modulated optical signal is mixed with a local oscillator (303) signal, which is then incident on a photodetector (305). The resultant microwave-frequency signal is then applied over a two-wire transmission line (308) to the Josephson junction (307) for direct demodulation.
9 Citations
15 Claims
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1. A demodulator for detecting a digital signal that is frequency-shift-keyed modulated onto a carrier signal comprising:
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a Josephson junction; means for applying the modulated carrier signal to said Josephson junction; means for directly detecting the ONEs and ZEROs of said digital signal from voltage variations generated across said Josephson junction in response to said applied modulated carrier signal. - View Dependent Claims (2, 3)
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4. A demodulator for demodulating a digital signal that is frequency-shift-keyed (FSK) modulated onto an optical signal comprising:
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means for converting said modulated optical signal to an intermediate microwave-frequency FSK modulated signal; a Josephson junction; means for applying said intermediate microwave-frequency modulated FSK signal to said Josephson junction over a transmission line; means for directly detecting the ONEs and ZEROs in said intermediate FSK signal from the voltage variations that are generated across said Josephson junction. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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12. A method of detecting a digital signal that is frequency-shift-keyed modulated onto a carrier signal comprising the steps of:
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applying the modulated carrier signal to a Josephson junction; and directly detecting the ONEs and ZEROs of the digital signal from voltage variations generated across the Josephson junction in response to the applied modulated carrier signal. - View Dependent Claims (13)
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14. A method of detecting a digital signal that is frequency-shift-keyed modulated onto an optical signal comprising the steps of:
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converting the modulated optical signal to an intermediate microwave-frequency FSK modulated signal; applying the intermediate microwave-frequency FSK signal to a Josephson junction; and directly detecting the ONEs and ZEROs of the digital signal from voltage variations generated across the Josephson junction in response to the applied microwave-frequency FSK signal. - View Dependent Claims (15)
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Specification