H04Q 1/448
With conversion of a single frequency signal into a digital signal
Official title: with conversion of a single frequency signal into a digital signal
H04Q1/448 (With conversion of a single frequency signal into a digital signal) appears on 29 US grants and 0 published applications in this corpus.
Search patents in H04Q- Granted patents
- 29
- Published applications
- 0
- Assignees
- 20
- Inventors
- 48
- Latest grant
- 24 Mar 1992
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 3 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 5 | 0 |
| 1981 | 1 | 0 |
| 1982 | 2 | 0 |
| 1983 | 1 | 0 |
| 1984 | 1 | 0 |
| 1985 | 4 | 0 |
| 1986 | 2 | 0 |
| 1987 | 2 | 0 |
| 1988 | 0 | 0 |
| 1989 | 2 | 0 |
| 1990 | 1 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
By publication year. Applications have been published since 2001.
Subgroups
Granted patents
Recent patents
- Method for suppressing quantization noises superimposed on a sinusoidal audible tone transmitted in a digital telecommunications exchange system24 Mar 1992US 5,099,498 ASiemens Aktiengesellschaft
- Digital composite tone alerting20 Nov 1990US 4,972,466 ANorthern Telecom Limited
- Detection of single-frequency signals18 Jul 1989US 4,849,688 ADialogic Corporation
- Audio frequency signal identification apparatus10 Jan 1989US 4,797,931 AKokusai Denshin Denwa Kabushiki Kaisha
- Signal detection and discrimination using waveform peak factor22 Sep 1987US 4,696,031 AWang Laboratories, Inc.
No published applications in this class yet.
Most cited
By later US patents
- Signal detection and discrimination using waveform peak factor53US 4,696,031 AWang Laboratories, Inc. · 1987
- 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