Radio transmission timing calibrator
First Claim
1. A software-defined communications device comprising:
- a modulator for generating a transmission sample including a sample stream and a waveform burst; and
a demodulator connected to the modulator and receiving the sample stream via a closed loop feedback path, the demodulator for determining a timing error of the transmission sample and for transmitting a timing error correction value to the modulator via the closed loop feedback path to enable the modulator to adjust a transmission time of a subsequent waveform burst by modifying the content of a subsequent sample stream of a subsequent transmission sample based on the timing error correction value.
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Accused Products
Abstract
A signal calibrator (14) for a software-defined communications device (10) that enables device communications signals to be transmitted in a manner that maximally decouples the calibrator (14) from the device hardware (40), and that simplifies the design and reduces the cost of the communications device (10). The calibrator (14) includes a software modulator (16) for generating a nonstop stream of samples including zero valued samples and non-zero valued waveform bursts, and a software demodulator (18) connected to the software modulator (16) via a closed loop feedback path (20) that receives a nonstop stream of samples. The non-zero valued samples create radio emissions. The software demodulator (18) is for determining a timing error of the transmission sample and for transmitting a timing error correction value to the software modulator (16) via the closed loop feedback path (20). The timing error correction value enables the software modulator (16) to adjust a transmission time of a subsequent waveform burst to compensate for both unknown hardware delays and RF signal propagation delays.
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Citations
19 Claims
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1. A software-defined communications device comprising:
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a modulator for generating a transmission sample including a sample stream and a waveform burst; and
a demodulator connected to the modulator and receiving the sample stream via a closed loop feedback path, the demodulator for determining a timing error of the transmission sample and for transmitting a timing error correction value to the modulator via the closed loop feedback path to enable the modulator to adjust a transmission time of a subsequent waveform burst by modifying the content of a subsequent sample stream of a subsequent transmission sample based on the timing error correction value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19)
a modulator pipeline connected to the modulator for providing an outlet path for the sample stream and the waveform burst;
a transmitter for transmitting the sample stream and the waveform burst, and for receiving the sample stream and the waveform burst from the modulator pipeline;
a receiver for receiving the sample stream transmitted by the transmitter; and
a demodulator pipeline for providing a return path for the sample stream received by the receiver.
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14. A method for calibrating a software-defined communications device signal modulator, comprising:
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outputting zero valued data samples into a continuous sample stream until a predetermined sample count is reached;
inserting a waveform burst into the continuous sample stream after the predetermined sample count is reached;
receiving an error correction value calculated from a difference between an actual sample stream transmit time and a calculated sample stream transit time;
increasing the zero valued data samples by a predetermined number during a subsequent outputting of zero valued data samples to compensate for the error correction value if the error correction value is greater than zero; and
decreasing the zero valued data samples by a predetermined number during a subsequent outputting of zero valued data samples to compensate for the error correction value if the terror correction value is less than zero. - View Dependent Claims (15, 16, 17, 18)
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Specification