Device and method for SPR detection in a mode-S transponder
First Claim
1. A method for qualifying a sync phase reversal (SPR) signal in a Mode-S transponder, comprising:
- receiving a Mode-S signal;
detecting a state change in the Mode-S signal from a first state to a second state, said state change representing a phase shift in the Mode-S signal; and
once the state change is detected, determining whether the Mode-S signal remains at the second state for a predefined minimum length of time sufficient to qualify the state change as a detector enable signal.
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Accused Products
Abstract
A method is provided for controlling transponder replies to Mode-S interrogation signals. The method includes receiving Mode-S signals containing P5 and P6 pulses each having certain amplitudes. Each P6 pulse contains a sync phase reversal (SPR) signal followed by a data segment containing Mode-S data. The P5 pulse is asynchronous with respect to the P6 pulse and is timed to overlay the SPR signal. The method includes, analyzing each P5 and corresponding P6 pulse, identifying the SPR signal correctly in the received Mode-S signals in which the amplitude of the P6 pulse is at least 12 dB greater than the amplitude of the P5 pulse and in no more than 2% of the received Mode-S signals in which the amplitude of the P6 pulse is at least 3 dB less than the amplitude of the P5 pulse, and replying to the Mode-S signals where the SPR signal is correctly identified.
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Citations
9 Claims
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1. A method for qualifying a sync phase reversal (SPR) signal in a Mode-S transponder, comprising:
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receiving a Mode-S signal;
detecting a state change in the Mode-S signal from a first state to a second state, said state change representing a phase shift in the Mode-S signal; and
once the state change is detected, determining whether the Mode-S signal remains at the second state for a predefined minimum length of time sufficient to qualify the state change as a detector enable signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification