| 摘要 |
PROBLEM TO BE SOLVED: To provide a satellite broadcast tuner that can cover a broadband. SOLUTION: A first stage IF tuner section is provided with two systems of BPFs 26, 30 and VCOs 33, 34 that are respectively designed to cover two divisions of a broadband reception frequency range (950 MHz-2650 MHz) and an AGC/VCO control section 37 controls selection of the BPFs 26, 30 and the VCOs 33, 34. In the case of receiving a low-band signal, the AGC/VCO control section 37 increases the delay in attenuators 28, 31 of a high-band AGC circuit to provide a signal passing through the low-band BPF 26 to a mixer 32 thereby driving the low-band VCO 33. In the case of receiving a high band signal, the AGC/VCO control section 37 increases the delay in attenuators 24, 27 of a low-band AGC circuit to provide a signal passing through the high-band BPF 30 to the mixer 32 thereby driving the high-band VCO 34.
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