Communications device using measured signal-to-noise ratio to adjust phase and frequency tracking
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04K-001/10
H03D-001/00
H04J-003/06
출원번호
US-0211995
(2008-09-17)
등록번호
US-8565324
(2013-10-22)
발명자
/ 주소
Furman, William N.
Nieto, John W.
Tyler, William L.
출원인 / 주소
Harris Corporation
대리인 / 주소
Allen, Dyer, Doppelt, Milbrath & Gilchrist, P.A.
인용정보
피인용 횟수 :
0인용 특허 :
18
초록▼
A communications device includes a phase and frequency tracking loop having a signal input and adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communication signals received at the signal input and processed within the tracking loop. A tracking loop upd
A communications device includes a phase and frequency tracking loop having a signal input and adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communication signals received at the signal input and processed within the tracking loop. A tracking loop update circuit updates the loop filter operating parameters. It is operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the measured signal-to-noise ratio in the received samples of communication signals at the signal output by the tracking loop and on the known or measured apriori tracking capabilities of demodulator based on the symbol rate of communication signal.
대표청구항▼
1. A communications device, comprising: a phase and frequency tracking loop having a signal input and an adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communications signals received at the signal input and processed within the tracking loop; anda tra
1. A communications device, comprising: a phase and frequency tracking loop having a signal input and an adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communications signals received at the signal input and processed within the tracking loop; anda tracking loop update circuit that updates loop filter operating parameters and operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the current symbol rate and on the measured signal-to-noise ratio in the received samples of communications signals at the signal input to the tracking loop. 2. The communications device according to claim 1, wherein the tracking bandwidth within the phase and frequency tracking loop is reduced based on the symbol rate and when the signal-to-noise ratio within the received samples of the communication signal has been reduced. 3. The communications device according to claim 1, wherein said tracking loop update circuit further comprises a signal-to-noise ratio estimator that receives the samples of communications signals and estimates the noise level within the communications signals that are output by the tracking loop. 4. The communications device according to claim 1, wherein the tracking loop update circuit further comprises a symbol rate configuration circuit that is operative for determining a symbol rate tracking capability, and said tracking loop update circuit updates the tracking loop parameters based on the measured signal-to-noise ratio and the symbol rate tracking capability. 5. The communications device according to claim 1, wherein said tracking loop update circuit further comprises a burst history circuit that is operative for maintaining a history of previous signal receptions to determine a signal burst history, and said tracking loop update circuit updates the tracking loop parameters based on the measured signal-to-noise ratio and the signal burst history. 6. The communications device according to claim 1, wherein said tracking loop update circuit further comprises a frequency offset and frequency-delta tracking circuit that is operative for determining the dynamics of the frequency offset of measured samples from the loop filter over time, and said tracking loop update circuit updates loop filter operating parameters based on the measured signal-to-noise ratio and the dynamics of the frequency offset of measured samples from the loop filter over time. 7. The communications device according to claim 1, wherein the tracking loop update circuit further comprises a filter bandwidth logic circuit connected to the loop filter that calculates the updated filter parameters and generates the updated filter parameters to the loop filter. 8. The communications device according to claim 1, wherein said phase and frequency tracking loop comprises a phase-locked loop circuit. 9. The communications device according to claim 8, wherein said phase-locked loop circuit further comprises a mixer connected to the signal input, a phase detector that receives signals output from the mixer and connected to the loop filter, and a numerically controlled oscillator connected to the mixer and the output of the loop filter. 10. The communications device according to claim 1, wherein said tracking loop update circuit is operative for updating filter parameters for tracking a Demand Assigned Multiple Access (DANA) waveform. 11. The communications device according to claim 1, and further comprising a demodulator that incorporates the phase and frequency tracking loop and the tracking loop update circuit. 12. A phase-locked loop circuit in a communications device, comprising: a signal input;a mixer connected to the signal input;a phase detector that receives signals output from the mixer;an adjustable loop filter connected to the phase detector that establishes a tracking loop bandwidth for samples of communications signals received at the signal input and processed by the phase-locked loop;a numerically controlled oscillator connected to the mixer and the output of the loop filter; anda loop update circuit comprising a signal-to-noise ratio estimator that receives signals and estimates the noise level within the communications signals and a filter bandwidth logic circuit connected to the loop filter and signal-to-noise ratio estimator that calculates updated filter parameters and generates the updated filter parameters to the loop filter for increasing or decreasing the tracking loop bandwidth based on the measured signal-to-noise ratio in the received samples of communications signals and on the symbol rate of the communications signal. 13. The phase-locked loop circuit according to claim 12, wherein the tracking bandwidth is reduced when the signal-to-noise ratio within received samples of communications signals has been reduced. 14. The phase-locked loop circuit according to claim 12, wherein said loop update circuit further comprises a symbol rate configuration circuit connected to the filter bandwidth logic circuit and operative for determining the apriori known tracking capability of waveform for the current symbol rate, and said filter bandwidth logic circuit calculates updated filter parameters based on the measured signal-to-noise ratio and the current symbol rate tracking capability. 15. The phase-locked loop circuit according to claim 12, wherein said loop update circuit further comprises a frequency offset and frequency-delta tracking circuit connected to the filter bandwidth logic circuit and operative for determining the dynamics of the frequency offset of measured samples from the loop filter over time, and said filter bandwidth logic circuit calculates updated filter parameters based on the measured signal-to-noise ratio and the frequency offset dynamics of measured samples from the loop filter over time. 16. The phase-locked loop circuit according to claim 12, wherein said loop update circuit further comprises a burst history circuit connected to the filter bandwidth logic circuit and operative for maintaining a history of previous signal receptions to determine a signal burst history, and said filter bandwidth logic circuit calculates updated filter parameters based on the measured signal-to-noise ratio and the signal burst history. 17. A method of communicating data, comprising: receiving a communications signal within a phase and frequency tracking loop having an adjustable loop filter;establishing a predetermined tracking loop bandwidth for samples of received communications signals processed within the tracking loop;determining the signal-to-noise ratio in received samples of the communications signals;determining the tracking capabilities of demodulator based on communication signal symbol rate; andupdating loop filter operating parameters to increase or decrease the bandwidth of the phase and frequency tracking loop based on the tracking capabilities of the demodulator for the given symbol rate of communication signal and the measured signal-to-noise ratio in the received samples of communications signals at the signal output by the tracking loop. 18. The method according to claim 17, which further comprises reducing the tracking bandwidth within the phase and frequency tracking loop when the signal-to-noise ratio within received samples of communications signals has been reduced. 19. The method according to claim 17, which further comprises determining a tracking capability of demodulator based on the symbol rate, and updating the tracking loop parameters based on the measured signal-to-noise ratio and the apriori known demodulator tracking capabilities based on the symbol rate. 20. The method according to claim 17, which further comprises maintaining a history of previous signal receptions to determine a signal burst history, and the tracking loop update circuit updates the tracking loop parameters based on the measured signal-to-noise ratio and the signal burst history. 21. The method according to claim 17, which further comprises determining the dynamics of the frequency offset of measured samples from the loop filter over time, and the tracking loop update circuit updates loop filter operating parameters based on the measured signal-to-noise ratio and the dynamics of the frequency offset of measured samples from the loop filter over time. 22. The method according to claim 17, which further comprises updating filter parameters for tracking a Demand Assigned Multiple Access (DAMA) waveform. 23. The method according to claim 17, which further comprises processing the communications signals within a phase-locked loop circuit comprising a mixer connected to the signal input, a phase detector that receives signals output from the mixer and connected to the loop filter, and numerically controlled oscillator connected to the mixer and the output of the loop filter. 24. A communications device, comprising: a phase and frequency tracking loop having a signal input and an adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communications signals received at the signal input and processed within the tracking loop; anda tracking loop update circuit that updates loop filter operating parameters and operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the current symbol rate and on the measured signal-to-noise ratio in the received samples of communications signals at the signal input to the tracking loop, wherein the tracking bandwidth within the phase and frequency tracking loop is reduced based on the symbol rate and when the signal-to-noise ratio within the received samples of the communication signal has been reduced. 25. A communications device, comprising: a phase and frequency tracking loop having a signal input and an adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communications signals received at the signal input and processed within the tracking loop; anda tracking loop update circuit that updates loop filter operating parameters and operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the current symbol rate and on the measured signal-to-noise ratio in the received samples of communications signals at the signal input to the tracking loop, wherein the tracking loop update circuit further comprises a symbol rate configuration circuit that is operative for determining a symbol rate tracking capability, and said tracking loop update circuit updates the tracking loop parameters based on the measured signal-to-noise ratio and the symbol rate tracking capability. 26. A method of communicating data, comprising: receiving a communications signal within a phase and frequency tracking loop having an adjustable loop filter;establishing a predetermined tracking loop bandwidth for samples of received communications signals processed within the tracking loop;determining the signal-to-noise ratio in received samples of the communications signals;determining the tracking capabilities of demodulator based on communication signal symbol rate;updating loop filter operating parameters to increase or decrease the bandwidth of the phase and frequency tracking loop based on the tracking capabilities of the demodulator for the given symbol rate of communication signal and the measured signal-to-noise ratio in the received samples of communications signals at the signal output by the tracking loop; andupdating the tracking loop parameters based on the measured signal-to-noise ratio and the apriori known demodulator tracking capabilities based on the symbol rate.
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