Frequency converter used for a receiver which receives signals of a UHF band or a microwave band
US4731875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1986 |
| Grant date | Mar 15, 1988 |
| Priority date | — |
| Expiry date | Feb 10, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D7/18
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency converter which is capable of rejecting unnecessary signals generated by image signals. The frequency converter has first and second local oscillation circuits which generate local oscillation signals whose frequencies are the same and whose phases are different by 90 degrees from each other. The converter further includes two mixer circuits, and a hybrid coupler. The mixer circuits generate two unnecessary signals whose phases are different by 90 degrees from each other. The hybrid coupler delays one unnecessary signal by a quarter of a wavelength to generate two unnecessary signals whose phases are different by 180 degrees from each other, so that they are cancelled by each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.