{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-9793999","patent":{"patent_number":"US-9793999","title":"System and method for 400G signal generation and coherent detection","assignee":null,"inventors":[],"filing_date":"2013-08-15T00:00:00.000Z","publication_date":"2017-10-17T00:00:00.000Z","cpc_codes":["H04B","H04B","H04B","H04B","H04B","H04J","H04L"],"num_claims":26,"abstract":"A novel digital signal processing scheme (DSP) for quadrature duobinary (QDB) spectrum shaped polarization multiplexed quadrature phase shift keying (PM-QPSK) based on multi-modulus blind equalizations (MMBE) is proposed and demonstrated with both simulation and experimental results. The key algorithms for this novel digital signal processing scheme include the cascaded multi-modulus algorithm (CMMA) for blind polarization de-multiplexing, multi-modulus QPSK partitioning frequency offset estimation (FOE) and two stage carrier phase recovery (CPR) with maximum likelihood phase estimation. The final signal is detected by maximum-likelihood sequence detection (MLSD) for data BER measurement. The feasibility of the proposed digital signal processing scheme is demonstrated by the experiment of 112 Gb/s QDB spectrum shaped PM-QPSK signal with a 25 GHz bandwidth waveshaper for Nyquist WDM channels."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"System and method for 400G signal generation and coherent detection","description":"A novel digital signal processing scheme (DSP) for quadrature duobinary (QDB) spectrum shaped polarization multiplexed quadrature phase shift keying (PM-QPSK) based on multi-modulus blind equalization","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-9793999","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-9793999","citation_suggestion":"Patentable. \"System and method for 400G signal generation and coherent detection\" (US-9793999). https://patentable.app/patents/US-9793999","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-9793999","json":"https://patentable.app/api/llm-context/US-9793999","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-06-06T05:40:48.065Z"}