Circuitry for characterizing speech for tamper protected recording
US4706293A · kind A · utility
1Cited by
9References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 10, 1984 |
| Grant date | Nov 10, 1987 |
| Priority date | — |
| Expiry date | Aug 10, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2020/10546
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Circuitry usable in a tamper protected recording system for characterizing audio signals at the time of recording including a filter for selecting a portion of the audio signal, a zero crossing detector to detect zero crossings, a threshold detector to determine when the threshold of the detector is satisfied, a first microprocessor for counting the zero crossing detections for successive time intervals and determining for each of the time intervals whether the threshold was satisfied and a second microprocessor for converting the counts and threshold information into data signals that can be recorded with the audio signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.