Coherent processing tunnel diode ultra wideband receiver
US5337054A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1992 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | May 18, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S7/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A four-terminal network in tandem with a tunnel diode (TD) threshold receiver currently used in radar or communications improves its sensitivity. Previous inventors have shown that the temperature and sensitivity properties of a conventional TD threshold device used for detecting very short duration bursts of microwave energy would be enhanced by appropriately biasing the TD by a current derived from the thermal noise; the current sets the TD operating point. The magnitude of the current is determined by a constant false alarm rate (CFAR) feedback loop. The subject invention recognizes that a TD changes states (i.e., a detection event) when the area under the current vs. time curve or the charge passing through the device exceeds a prescribed number of picocoulombs. To maximize the charge and improve detection, a form of superheterodyne conversion is introduced to convert the oscillatory short pulse microwave signal received by an antenna to a monopolar baseband signal. This is done by mixing the incoming signal with a CW carrier whose frequency is precisely chosen so that the resulting beat frequency is one-half of an rf cycle for the given duration of the microwave burst. This ma…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.