{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-9599556","patent":{"patent_number":"US-9599556","title":"Reference signal generation for lock-in amplifier in high sensitivity gas sensing system","assignee":null,"inventors":[],"filing_date":"2016-04-04T00:00:00.000Z","publication_date":"2017-03-21T00:00:00.000Z","cpc_codes":["G01N","G01N","G01N"],"num_claims":19,"abstract":"A gas sensing system includes a signal generator including a wavelength tunable laser, the signal generator providing a first periodic signal and a second periodic signal, wherein the first periodic signal comprises a wavelength scanning signal and the second periodic signal comprises a modulation signal; an optical signal absorption path which is wavelength selective, wherein the generated signal covers at least one of the absorbance band; a signal detector that uses lock-in detection to detect a second harmonic of the second periodic signal after absorption, the signal detector further including a local reference generator, a multiplier, and a low pass filter; a local reference includes a first path (ref1) that outputs sinusoidal signal with frequency equals to that of the second signal in signal generator, and a second path (ref2) that outputs sinusoidal signal of two times ref1 frequency; and a local reference generator having a first phase shifter that is configurable from 0 to 2π and a second phase shifter that shifts 90-degree, wherein the first phase shifter is for an alignment of ref1 with the modulation signal and the second phase shifter provides 90-degree shifts for ref2 from ref1, wherein the first and second paths (ref1 and ref2) are selected by a switch, wherein the switch uses the first path during initialization and the second path for normal operation."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Reference signal generation for lock-in amplifier in high sensitivity gas sensing system","description":"A gas sensing system includes a signal generator including a wavelength tunable laser, the signal generator providing a first periodic signal and a second periodic signal, wherein the first periodic s","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-9599556","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-9599556","citation_suggestion":"Patentable. \"Reference signal generation for lock-in amplifier in high sensitivity gas sensing system\" (US-9599556). https://patentable.app/patents/US-9599556","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-9599556","json":"https://patentable.app/api/llm-context/US-9599556","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-06-06T06:09:40.049Z"}