Pulse induction metal detector
US5414411A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 21, 1993 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Jun 21, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Metal detector apparatus includes an increased pulse transmit frequency and reduced integration time constant for rapid target response and improved sensitivity to low conductivity metals, including cupro-nickel alloys, platinum and gold. Resistor-capacitor (RC) coupling totally eliminates the need to reset the controls due to changes in temperature or mineralization in the area being searched. The short time constant used in the RC coupling circuit improves the overall stability while reducing noise, allowing for greater amplification in the audio stages. The time constant of the RC coupling stage is equal or similar to the time constant of the integrator. The audio tone is derived from the pulse transmit clock which is synchronous with the power supply inverter to reduce noise and instability in the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.