System for measuring the distance between two stations mobile with regard to one another
First Claim
1. A system for measuring a distance between first and second stations mobile with regard to one another,said second station comprising means for modulating a carrier signal emitted from said first station by a digital signal into a two-phase-state modulated signal which is transmitted to said first station, andsaid first station comprising:
- means for demodulating and filtering said two-phase-state modulated signal into two phase-quadrature demodulated and filtered signals,means for deriving a first logic signal having logic levels dependent on the sign of a product of said two phase-quadrature demodulated and filtered signalsmeans for deriving a second logic signal having logic levels dependent on the sign of the difference of the moduli of said two phase-quadrature demodulated and filtered signals,first means for generating first and second pulses respectively in response to first and second transitions in one of the first and second logic signals respectively when the other one of the first and second logic signals is at first and second logic levels, and in response to said first and second transitions in said one of the first and second logic signals respectively when said other one of the first and second logic signals is at said second and first logic levels, andup-down counting means for counting up said first pulses and counting down said second pulses thereby deriving a pulse count representative of said distance.
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Accused Products
Abstract
An emitted wave is transmitted from a central station to a passive end. A phase modulation circuit in the passive end modulates a signal resulting from the emitted wave for retransmitting it in the form of a two-phase-state modulated signal at the rhythm of a clock signal. In the central station, the modulated signal is demodulated into two quadrature signals. On the basis of the product of the two quadrature signals and the sign of the difference between the moduli of the rectified quadrature signals, the count of an up-down counter in a digital processing circuit is incremented or decremented in order for said count to be representative of the distance separating the passive end and the central station.
17 Citations
7 Claims
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1. A system for measuring a distance between first and second stations mobile with regard to one another,
said second station comprising means for modulating a carrier signal emitted from said first station by a digital signal into a two-phase-state modulated signal which is transmitted to said first station, and said first station comprising: -
means for demodulating and filtering said two-phase-state modulated signal into two phase-quadrature demodulated and filtered signals, means for deriving a first logic signal having logic levels dependent on the sign of a product of said two phase-quadrature demodulated and filtered signals means for deriving a second logic signal having logic levels dependent on the sign of the difference of the moduli of said two phase-quadrature demodulated and filtered signals, first means for generating first and second pulses respectively in response to first and second transitions in one of the first and second logic signals respectively when the other one of the first and second logic signals is at first and second logic levels, and in response to said first and second transitions in said one of the first and second logic signals respectively when said other one of the first and second logic signals is at said second and first logic levels, and up-down counting means for counting up said first pulses and counting down said second pulses thereby deriving a pulse count representative of said distance. - View Dependent Claims (2, 3, 4)
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5. A system for measuring a distance between first and second stations mobile with regard to one another,
said second station comprising means for modulating a carrier signal emitted from said first station by a digital signal into a two-phase-state modulated signal which is transmitted to said first station, and said first station comprising: means for demodulating and filtering said two-phase-state modulated signal into two phase-quadrature demodulated and filtered signals, means for deriving a first logic signal having logic levels dependent on the sign of a product of said two phase-quadrature demodulated and filtered signals, means for deriving a second logic signal having logic levels dependent on the sign of the difference of the moduli of said two phase-quadrature demodulated and filtered signals, first means for generating first and second pulses respectively in response to first and second transitions in one of the first and second logic signals respectively when the other one of the first and second logic signals is at first and second logic levels, and in response to said first and second transitions in said one of the first and second logic signals respectively when said other one of the first and second logic signals is at said second and first logic levels, second means for generating first and second pulses respectively in response to first and second transitions in said other one of the first and second logic signals respectively when said one of the first and second logic signals is at first and second logic levels, and in response to said first and second transitions in said other one of the first and second logic signals respectively when said one of the first and second logic signals is at said second and first logic levels, and up-down counting means for counting up said first pulses generated by said first and second generating means and counting down said second pulses generated by said first and second generating means thereby deriving a pulse count representative of said distance. - View Dependent Claims (6, 7)
Specification