Apparatus and method for determining single sideband noise figure from double sideband measurements
US5416422A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1994 |
| Grant date | May 16, 1995 |
| Priority date | — |
| Expiry date | May 20, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R29/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A single sideband noise figure of a device under test is determined from double sideband measurements. A noise measurement system is provided, which includes a noise source, a mixer, a local oscillator, and a tunable intermediate frequency receiver. Three independent measurements are performed (one with the local oscillator frequency on the high side of the RF measurement frequency, another with the local oscillator frequency on the low side of the RF measurement frequency, and the third with the local oscillator frequency at the RF measurement frequency and the intermediate frequency at twice its former frequency). These noise power measurements are combined in such a way as to cancel the unwanted sidebands. Preferably, three output noise power measurements are also performed during a calibration so that the subsequent measurements are corrected for impedance mismatch errors. The complexity and cost of performing accurate single sideband noise figure measurements are reduced compared to conventional single sideband measurement systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.