H04Q 1/4485
Which is transmitted in digital form
Official title: {which is transmitted in digital form}
H04Q1/4485 (Which is transmitted in digital form) appears on 13 US grants and 0 published applications in this corpus.
Search patents in H04Q- Granted patents
- 13
- Published applications
- 0
- Assignees
- 8
- Inventors
- 22
- Latest grant
- 20 Nov 1990
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 3 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 1 | 0 |
| 1985 | 3 | 0 |
| 1986 | 1 | 0 |
| 1987 | 1 | 0 |
| 1988 | 0 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
By publication year. Applications have been published since 2001.
Recent patents
- Digital composite tone alerting20 Nov 1990US 4,972,466 ANorthern Telecom Limited
- Audio frequency signal identification apparatus10 Jan 1989US 4,797,931 AKokusai Denshin Denwa Kabushiki Kaisha
- Switching system having tone trunk14 Jul 1987US 4,680,758 AFujitsu Limited
- Tone receiver for digital data communication systems7 Jan 1986US 4,563,681 AInternational Business Machines Corporation
- Digital automatic gain control circuit for PCM signals3 Sep 1985US 4,539,692 ANorthern Telecom Limited
No published applications in this class yet.
Most cited
By later US patents
- Call progress signal monitor and method for telephone systems50US 4,528,664 ANorthern Telecom Limited · 1985
- Sampled signal detector28US 4,064,488 AMotorola, Inc. · 1977
- Digital circuit and method for the detection of call progress tones in telephone systems25US 4,439,639 ANorthern Telecom Limited · 1984
- Digital signal detector21US 4,197,502 AMotorola, Inc. · 1980
- Audio frequency signal identification apparatus20US 4,797,931 AKokusai Denshin Denwa Kabushiki Kaisha · 1989