Image rejection mixer and terrestrial digital multimedia broadcasting tuner of low intermediate frequency structure using the same

摘要

Disclosed herein are a terrestrial digital multimedia broadcasting (DMB) tuner of a low intermediate frequency (IF) structure which is applied to a mobile communication terminal, such as a mobile phone, and an image rejection mixer applied thereto. In order to improve inter-channel attenuation characteristics, the image rejection mixer locates an oscillation frequency above or beneath the frequency of a target signal to include an image signal of the target signal in a terrestrial DMB band, mixes a radio frequency (RF) signal with the oscillation frequency, and outputs the resulting IF signals to a polyphase filter in a selected arrangement. Because the image signal of the target signal is included in the terrestrial DMB band, the image rejection mixer can satisfy the inter-channel attenuation characteristics without a troublesome or complex design.