FREQUENCY CONVERTER USED FOR A RECEIVER WHICH RECEIVES SIGNALS OF A UHF BAND OR A MICROWAVE BAND

摘要

- 1 -Abstract:The invention provides a frequency converter which iscapable of rejecting unnecessary signals generated byimage signals. The frequency converter has first andsecond local oscillation circuits which generate localoscillation signals whose frequencies are the same andwhose phases are different by 90 degrees from each other,has two mixer circuits, and has a hybrid coupler. Themixer circuits generate two unnecessary signals whosephases are different by 90 degrees from each other. Thehybrid coupler delays one unnecessary signal by a quarterof the wavelength to generate two unnecessary signalswhose phases are different by 180 degrees from each other,so that they are cancelled by each other.