| 摘要 |
<P>PROBLEM TO BE SOLVED: To make an order of a filter low without reducing receiving sensitivity to attain miniaturization and cost reduction in a television broadcast receiving circuit built in a mobile communication terminal. <P>SOLUTION: The television broadcast receiving circuit 30 is provided with a bandwidth variable filter 31 between a low noise amplifier 12 and a variable amplifier circuit 15, and a BW control circuit 32 which switches filter characteristics of the bandwidth variable filter 31 by being synchronized with a channel selection signal. When a frequency of cellular phone transmitted wave and a broadcast receiving frequency are in combination for generating a spurious response, a first attenuation mode with a large attenuation amount is set by making a BW switching signal to be applied from the control circuit 32 to a transistor SW1 active. In addition, the frequency of the cellular phone transmitted wave and the broadcast receiving frequency are in combination for generating no spurious response, a second attenuation mode with a small attenuation amount is set by making the BW switching signal to be applied from the control circuit 32 to the transistor SW1 non-active. <P>COPYRIGHT: (C)2010,JPO&INPIT |
