H04M 9/087
Using different frequency bands for transmitting and receiving paths
Official title: {using different frequency bands for transmitting and receiving paths (for line transmission in general H04B3/21); using phase shifting arrangements}
H04M9/087 (Using different frequency bands for transmitting and receiving paths) appears on 12 US grants and 5 published applications in this corpus.
Search patents in H04M- Granted patents
- 12
- Published applications
- 5
- Assignees
- 10
- Inventors
- 29
- Latest grant
- 19 May 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 1 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 2 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 1 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 1 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 1 |
| 2016 | 0 | 0 |
| 2017 | 1 | 0 |
| 2018 | 0 | 1 |
| 2019 | 1 | 0 |
| 2020 | 0 | 1 |
| 2021 | 0 | 0 |
| 2022 | 1 | 0 |
| 2023 | 0 | 0 |
| 2024 | 0 | 1 |
| 2025 | 0 | 0 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Clock skew robust acoustic echo cancellation19 May 2026US 12,634,397 B1Amazon Technologies, Inc.
- Receive-path signal gain operations14 Jun 2022US 11,363,147 B2Sorenson IP Holdings, LLC
- Echo canceller device and voice telecommunications device30 Jul 2019US 10,367,949 B2Mitsubishi Electric Corporation
- Communication device with echo suppression14 Nov 2017US 9,819,805 B2Sennheiser Communications A/S
- Noise reduction circuit for telephones28 Sep 2004US 6,798,881 B2Acoustic Technologies, Inc.
- Joint far-end and near-end speech intelligibility enhancement5 Dec 2024US 2024/0404543 A1Rtx A/S
- Receive-path signal gain operations26 Mar 2020US 2020/0099793 A1Sorenson IP Holdings, LLC
- Echo canceller device and voice telecommunications device29 Nov 2018US 2018/0343345 A1Mitsubishi Electric Corporation
- Communication device with echo suppression8 Jan 2015US 2015/0011266 A1Sennheiser Communications A/S
- Noise reduction circuit for telephones15 Nov 2001US 2001/0040963 A1Acoustic Technologies, Inc.
Most cited
By later US patents
- Audio processing system for teleconferencing with high and low transmission delays29US 5,386,465 ABell Communications Research, Inc. · 1995
- Voice enhancer system23US 4,965,833 A1990
- Audio processing system for teleconferencing system22US 5,271,057 ABell Communications Research, Inc. · 1993
- Audio processing system for point-to-point and multipoint teleconferencing19US 5,434,912 ABell Communications Research, Inc. · 1995
- Apparatus and method for hands free telephonic communication15US 4,819,263 ACellular Communications Corporation · 1989