Electron paramagnetic resonance (EPR) spectrometer
US4888554A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1988 |
| Grant date | Dec 19, 1989 |
| Priority date | — |
| Expiry date | Aug 2, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/60
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electron paramagnetic resonance (EPR) spectrometer employing a reference arm microwave bridge provides efficient, simultaneous generation of orthogonal I and Q signals. The simultaneous generation is enabled through the use of a field effect transistor (FET) microwave amplifier in the signal arm feeding a balanced quadrature mixer. The I and Q signals are then combined to produce a signal suitable for use as a discriminator in an automatic frequency control (AFC) circuit. An important characteristic of the discriminator signal is that it is independent of the relative phase angle .alpha. between the reference arm and signal arm of the bridge. In a further embodiment, an apparatus is disclosed which computes .alpha. from the I and Q signals, and uses the computed value for .alpha. to extract pure absorption and pure dispersion information from the I and Q signals regardless of the setting of .alpha. in the bridge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.