Autocalibrating interferometer
US4673944A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 12, 1984 |
| Grant date | Jun 16, 1987 |
| Priority date | — |
| Expiry date | Mar 12, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S3/46
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A direction-finding interferometer (100) includes a novel autocalibration subsystem using bi-directional transmissions at a common frequency. The interferometer determines direction using a primary phase comparator (15) to assess the phase differences in signals transmitted by signal channels (13) from multiple antennas (11). The signal channels may include RF amplifiers (17), mixers (19) coupled to a local oscillator (23), IF amplifiers (21), and transmission lines. The autocalibration subsystem employs a frequency synthesizer (25) as a calibration signal source. The calibration signal path is directed between reversing switches (40) and couplers (33) in alternating directions via transmission lines (57 and 59). In either direction, the calibration is split so that part of the signals are coupled into the signal channels, and the remaining part is directed to a secondary phase comparator (131). The outputs of the primary and secondary comparators provide the data necessary for autocalibration. Other embodiments provide for a secondary comparator operating at a frequency range similar to that of the primary comparator. Gain autocalibration is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.