# US 8,571,141 B2 · Carrier recovery device and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,571,141 B2 - Document ID: US8571141B2 - Status: Granted - Kind: B2 - Application number: 12/793,432 - Filed: 2010-06-03 - Published: 2010-12-09 - Granted: 2013-10-29 - Earliest claimed: 2009-06-03 - Assignees: Realtek Semiconductor Corp. - Applicants: Kuang-Peng Cheng; Ming-Chang Chen - Inventors: Kuang-Peng Cheng; Ming-Chang Chen - Web page: https://patentgrep.com/patent/US8571141B2 ## CPC - H04L 27/0014: {Carrier regulation (of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657)} - H04L 2027/0028: {at passband only} - H04L 2027/0057: {quadrature phase} - H04L 2027/0067: {Phase error detectors} - H04L 2027/0075: {Error weighting} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A carrier recovery device and a carrier recovery method are provided. The device includes a phase detection module, a computation module, a phase angle adjustment module, a loop filter, and a conversion module. The phase detection module receives an IF signal, and detects a sine and a cosine signals corresponding to the IF signal. The computation module receives the sine and the cosine signals, and computes a phase angle between the sine and the cosine signals. The phase angle adjustment module adjusts the phase angle according to one of the sine and the cosine signals and a threshold. The loop filter generates a frequency offset angle according to the phase angle. The conversion module generates a sine and a cosine parameters according to the frequency offset angle, and transfers the sine and the cosine parameters to the phase detection module. ## Claims ### Claim 1 A carrier recovery device, comprising: a phase detection module, for receiving an input signal and detecting a sine signal and a cosine signal in the input signal according to a sine parameter and a cosine parameter; a computation module, coupled to the phase detection module, for computing a phase angle between the sine signal and the cosine signal; a phase angle adjustment module, coupled to the phase detection module and the computation module, for adjusting the phase angle according to at least one of the sine signal or the cosine signal and a threshold, and outputting an adjusted phase angle, wherein the phase angle adjustment module compares the at least one of the sine signal or the cosine signal with the threshold, and reduces the phase angle when the at least one of the sine signal or the cosine signal is smaller than the threshold; a loop filter, coupled to the phase angle adjustment module, for generating a frequency offset angle according to the adjusted phase angle; and a conversion module, coupled to the loop filter and the phase detection module, for generating the sine parameter and the cosine parameter to the phase detection module according to the frequency offset angle. ### Claim 2 (depends on 1) The carrier recovery device according to claim 1, wherein the phase detection module comprises: a first multiplier, for multiplying the input signal by the sine parameter to generate the sine signal; and a second multiplier, for multiplying the input signal by the cosine parameter to generate the cosine signal. ### Claim 3 (depends on 1) The carrier recovery device according to claim 1, wherein the computation module comprises a coordinate rotation digital computer (CORDIC). ### Claim 4 (depends on 1) The carrier recovery device according to claim 1, wherein the loop filter comprises a proportional integral (PI) controller. ### Claim 5 (depends on 1) The carrier recovery device according to claim 1, wherein the conversion module comprises a local oscillator. ### Claim 6 (depends on 1) The carrier recovery device according to claim 1, wherein the conversion module generates the sine parameter and the cosine parameter according to a look up table. ### Claim 7 (depends on 1) The carrier recovery device according to claim 1, wherein the input signal is an intermediate frequency (IF) signal. ### Claim 8 A carrier recovery method, comprising: receiving an input signal, and detecting a sine signal and a cosine signal in the input signal according to a sine parameter and a cosine parameter; computing a phase angle between the sine signal and the cosine signal; adjusting the phase angle according to at least one of the sine signal or the cosine signal and a threshold, and outputting an adjusted phase angle, wherein the step of adjusting the phase angle comprises: comparing the at least one of the sine signal or the cosine signal with the threshold; and reducing the phase angle when the at least one of the sine signal or the cosine signal is smaller than the threshold; generating a frequency offset angle according to the adjusted phase angle; and generating the sine parameter and the cosine parameter according to the frequency offset angle, so as to adjust the sine signal and the cosine signal respectively. ### Claim 9 (depends on 8) The carrier recovery method according to claim 8, wherein the step of detecting the sine signal and the cosine signal comprises: multiplying the input signal by the sine parameter to generate the sine signal; and multiplying the input signal by the cosine parameter to generate the cosine signal. ### Claim 10 (depends on 8) The carrier recovery method according to claim 8, wherein the step of generating the sine parameter and the cosine parameter comprises: generating the sine parameter and the cosine parameter according to a look up table. ### Claim 11 A carrier recovery device, comprising: a phase detection module, for receiving an input signal and detecting a sine signal and a cosine signal in the input signal according to a sine parameter and a cosine parameter; a computation module, coupled to the phase detection module, for computing a phase angle between the sine signal and the cosine signal; a phase angle adjustment module, coupled to the phase detection module and the computation module, for adjusting the phase angle according to at least one of the sine signal or the cosine signal and a threshold, and outputting an adjusted phase angle, wherein the phase angle adjustment module computes a maximum value of the at least one of the sine signal or the cosine signal, takes a reciprocal of the maximum value to serve as the threshold, and multiplies the threshold by the phase angle; a loop filter, coupled to the phase angle adjustment module, for generating a frequency offset angle according to the adjusted phase angle; and a conversion module, coupled to the loop filter and the phase detection module, for generating the sine parameter and the cosine parameter to the phase detection module according to the frequency offset angle. ### Claim 12 (depends on 11) The carrier recovery device according to claim 11, wherein the phase angle adjustment module provides a weight for adjusting a weight value obtained after multiplying the threshold by the phase angle. ### Claim 13 (depends on 11) The carrier recovery device according to claim 11, wherein the phase detection module comprises: a first multiplier, for multiplying the input signal by the sine parameter to generate the sine signal; and a second multiplier, for multiplying the input signal by the cosine parameter to generate the cosine signal. ### Claim 14 (depends on 11) The carrier recovery device according to claim 11, wherein the computation module comprises a coordinate rotation digital computer (CORDIC). ### Claim 15 (depends on 11) The carrier recovery device according to claim 11, wherein the loop filter comprises a proportional integral (PI) controller. ### Claim 16 (depends on 11) The carrier recovery device according to claim 11, wherein the conversion module comprises a local oscillator. ### Claim 17 (depends on 11) The carrier recovery device according to claim 11, wherein the conversion module generates the sine parameter and the cosine parameter according to a look up table. ### Claim 18 (depends on 11) The carrier recovery device according to claim 11, wherein the input signal is an intermediate frequency (IF) signal.