Pulse or digital communications – Repeaters – Testing
Patent
1995-02-03
1996-02-27
Cain, David C.
Pulse or digital communications
Repeaters
Testing
375208, 375209, 375210, 380 48, H04L 900
Patent
active
054954991
ABSTRACT:
A receiver for pseudorandom noise (PRN) encoded signals consisting of a sampling circuit, multiple carrier and code synchronizing circuits, and multiple digital autocorrelators. The sampling circuit provides digital samples of a received composite signal to each of the several receiver channel circuits. The synchronizing circuits are preferably non-coherent, in the sense that they track any phase shifts in the received signal and adjust the frequency and phase of a locally generated carrier reference signal accordingly, even in the presence of Doppler or ionospheric distortion. The autocorrelators in each channel form a delay lock loop (DLL) which correlates the digital samples of the composite signal with locally generated PRN code values to produce a plurality of (early, late), or (punctual, early-minus-late) correlation signals. The time delay spacing between the (early, late), and (punctual, early-minus-late) correlation signals are dynamically adjusted, such that in an initial acquisition mode, the delay spacing is relatively wide, on the order of approximately one PRN code chip time; once PRN code lock is achieved, the code delay spacing is narrowed to a fraction of a PRN code chip time.
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Fenton Patrick
Van Dierendonck Albert J.
Cain David C.
NovAtel Communications Ltd.
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