Programmable digital acquisition and tracking controller
First Claim
1. A programmable digital acquisition and tracking controller for a PN communications receiver, comprising:
- summing means having programmable threshold inputs and a signal level input indicative of correlation of two PN codes,programmable accumulator means coupled to the output of said summing means for generating signals indicative of an average correlation value of said two PN codes within a programmable time period,programmable detector logic means coupled to the output of said programmable accumulator means and having a correlation detection signal output and a plurality of control signal outputs,programmable time counter means having a programmable input for producing a count output which is coupled to said detector logic means for presetting a value indicating the end of said programmable time period, andsaid output of said programmable detector logic circuit means being adapted to close a plurality of tracking loops in said communications receiver upon detection of correlation of said two PN codes and to initiate said control signals to maintain tracking.
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Abstract
A novel programmable digital acquisition and tracking controller is coupled to the input signal level from the demodulator of a communications receiver and provides programmable signal level threshold detectors and detection intervals adapted to produce an output signal which is indicative of the correlation between the received PN code and the locally generated PN code as compared against a programmable threshold. The programmable detector logic is capable of detecting acquisition correlation and tracking correlation and can optionally inform an external microprocessor of the correlation level so as to implement a wide variety of acquisition, tracking and reacquisition algorithms as well as optional AM demodulation.
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Citations
8 Claims
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1. A programmable digital acquisition and tracking controller for a PN communications receiver, comprising:
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summing means having programmable threshold inputs and a signal level input indicative of correlation of two PN codes, programmable accumulator means coupled to the output of said summing means for generating signals indicative of an average correlation value of said two PN codes within a programmable time period, programmable detector logic means coupled to the output of said programmable accumulator means and having a correlation detection signal output and a plurality of control signal outputs, programmable time counter means having a programmable input for producing a count output which is coupled to said detector logic means for presetting a value indicating the end of said programmable time period, and said output of said programmable detector logic circuit means being adapted to close a plurality of tracking loops in said communications receiver upon detection of correlation of said two PN codes and to initiate said control signals to maintain tracking. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification