# US 2014/0194076 A1 · Systems and methods for minimizing spurs through duty cycle adjustment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194076 A1 - Document ID: US20140194076A1 - Status: Published application - Kind: A1 - Application number: 13/738,917 - Filed: 2013-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: QUALCOMM Incorporated - Applicants: Qualcomm Incorporated - Inventors: Justin A. HWANG; David SU - Web page: https://patentgrep.com/patent/US20140194076A1 ## CPC - H04B 15/00: Suppression or limitation of noise or interference (by means associated with receiver H04B1/10) - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H04B 15/06: by local oscillators of receivers - H04B: TRANSMISSION ## Abstract A frequency source, such as for a wireless communications device, configured to have a duty cycle adjustment. A selected harmonic spur resulting from operation of the frequency source at one duty cycle may be avoided or minimized by operating the frequency source at a second duty cycle. Determination of the appropriate duty cycle may be based on measuring the amplitude of the harmonic spur as it appears in the output of a receive chain of the wireless device. Alternatively, the duty cycle may be set to desired value to avoid or minimize a given harmonic. ## Claims ### Claim 1 A method for reducing a harmonic spur comprising: operating a frequency source at a first duty cycle such that the harmonic spur has a first amplitude at the first duty cycle; and operating the frequency source at a second duty cycle, such that the harmonic spur has a second amplitude at the second duty cycle, wherein the second amplitude is less than the first amplitude. ### Claim 2 (depends on 1) The method of claim 1, wherein the second duty cycle corresponds to an integer multiple of a reciprocal of an order of the harmonic spur. ### Claim 3 (depends on 1) The method of claim 1, further comprising detecting an amplitude of the harmonic spur and adjusting the second duty cycle until the second amplitude of the harmonic spur is less than a threshold. ### Claim 4 (depends on 3) The method of claim 3, wherein detecting the amplitude of the harmonic spur comprises analyzing an output of a receive chain coupled to the frequency source. ### Claim 5 (depends on 1) The method of claim 1, further comprising measuring a duty cycle of the frequency source and adjusting operation of the frequency source until the frequency source operates at the second duty cycle. ### Claim 6 A frequency source comprising a duty cycle module, wherein when operation of the frequency source at a first duty cycle generates a harmonic spur having a first amplitude, the duty cycle module is configured to operate the frequency source at a second duty cycle, such that the harmonic spur has a second amplitude at the second duty cycle, wherein the second amplitude is less than the first amplitude. ### Claim 7 (depends on 6) The frequency source of claim 6, wherein the second duty cycle corresponds to an integer multiple of a reciprocal of an order of the harmonic spur. ### Claim 8 (depends on 6) The frequency source of claim 6, further comprising a duty cycle control module configured to detect an amplitude of the harmonic spur and adjust the duty cycle module to operate the frequency source at the second duty cycle such that the second amplitude of the harmonic spur is less than a threshold. ### Claim 9 (depends on 8) The frequency source of claim 8, wherein the duty cycle control module is configured to detect the amplitude of the harmonic spur by analyzing an output of a receive chain coupled to the frequency source. ### Claim 10 (depends on 6) The frequency source of claim 6, further comprising a duty cycle measurement unit configured to determine a duty cycle of the frequency source and the duty cycle module is configured to adjust the duty cycle of the frequency source until the duty cycle measurement unit determines the frequency source is operating at the second duty cycle. ### Claim 11 A method of operating a wireless communications device, comprising: operating a frequency source, wherein energy from the frequency source couples to a receive chain of the wireless communications device to generate a harmonic spur having a first amplitude when the frequency source operates at a first duty cycle; and operating the frequency source at a second duty cycle, such that the harmonic spur has a second amplitude at the second duty cycle, wherein the second amplitude is less than the first amplitude. ### Claim 12 (depends on 11) The method of claim 11, wherein the second duty cycle corresponds to an integer multiple of a reciprocal of an order of the harmonic spur. ### Claim 13 (depends on 11) The method of claim 11, further comprising detecting an amplitude of the harmonic spur and adjusting the second duty cycle such that the second amplitude of the harmonic spur is less than a threshold. ### Claim 14 (depends on 13) The method of claim 13, further comprising storing the second duty cycle as corresponding to an operational condition of the wireless communications device. ### Claim 15 (depends on 13) The method of claim 13, further comprising retrieving the second duty cycle from storage based on an operational condition of the wireless communications device, wherein the second duty cycle was determined previously. ### Claim 16 (depends on 13) The method of claim 13, wherein detecting the amplitude of the harmonic spur comprises analyzing an output of the receive chain. ### Claim 17 (depends on 11) The method of claim 11, further comprising measuring a duty cycle of the frequency source and adjusting operation of the frequency source until the frequency source operates at the second duty cycle. ### Claim 18 (depends on 12) The method of claim 12, further comprising retrieving the second duty cycle from storage based on an operational condition of the wireless communications device. ### Claim 19 A wireless communications device comprising: a receive chain; a frequency source; and a a duty cycle module, wherein operation of the frequency source at a first duty cycle generates a harmonic spur that couples to the receive chain having a first amplitude at the first duty cycle and wherein the duty cycle module is configured to operate the frequency source at a second duty cycle, such that the harmonic spur has a second amplitude at the second duty cycle and the second amplitude is less than the first amplitude. ### Claim 20 (depends on 19) The wireless communications device of claim 19, wherein the second duty cycle corresponds to an integer multiple of a reciprocal of an order of the harmonic spur. ### Claim 21 (depends on 19) The wireless communications device of claim 19, further comprising a duty cycle control module configured to detect an amplitude of the harmonic spur and adjust the second duty cycle until the second amplitude of the harmonic spur is less than a threshold. ### Claim 22 (depends on 21) The wireless communications device of claim 21, wherein the duty cycle control module is further configured to store the second duty cycle as corresponding to an operational condition of the wireless communications device. ### Claim 23 (depends on 21) The wireless communications device of claim 21, wherein the duty cycle control module is further configured to retrieve the second duty cycle from storage based on an operational condition of the wireless communications device, wherein the second duty cycle was determined previously. ### Claim 24 (depends on 21) The wireless communications device of claim 21, wherein the duty cycle control module is configured to detect the amplitude of the harmonic spur by analyzing an output of the receive chain. ### Claim 25 (depends on 19) The wireless communications device of claim 19, further comprising a duty cycle measurement unit configured to determine a duty cycle of the frequency source and wherein the duty cycle module is configured to adjust the duty cycle of the frequency source until the duty cycle measurement unit determines the frequency source is operating at the second duty cycle. ### Claim 26 (depends on 19) The wireless communications device of claim 19, wherein the duty cycle module is further configured to retrieve the second duty cycle from storage based on an operational condition of the wireless communications device.