DIFF Subgroup
H04B 3/20 Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Line transmission systems > Details > Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
CPC:
Line transmission systems (combined with near-field transmission systems H04B5/00) > Details > Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
IPC and CPC are identically structured here. All 2 subcodes exist in both systems.
IPC defines codes here since 1980.
Child Classifications
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- H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers since 1980 +6 CPC IPC+CPC Available in IPC and CPC