| 摘要 |
A digital tuner is provided to attenuate an inputted signal through an attenuator in case of a strong electric field to output the attenuated signal, without performing an attenuation process if the inputted signal has a weak electric field, thereby remarkably obtaining performance ranges of receive sensitivity of the tuner. An RF(Radio Frequency) input unit(200), which consists of a high-pass filter(201), a low noise amplifier(202), a band-pass filters(203,205) and a high-frequency amplifier(204), filters and outputs an inputted RF signal through a predetermined band. An MOPLL(Mixer Oscillator Phase Locked Loop) IC(Integrated Circuit)(210) converts the inputted RF signal into an IF(Intermediate Frequency) to output the converted signal. An IF amplifier(220) filters and amplifies the IF. A digital demodulator(230) demodulates the inputted IF into an original signal. An attenuator(240) attenuates a level of the inputted RF signal by a control signal of the IC(210).
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