| 摘要 |
An RF circuit ( 131-138 ) satisfies Pnoise+NF+G<=Plim+sW (0<=s<=4) at an edge of a guard band with respect to a required transmission level PAll, an upper tolerance level of out-of-band noise Plim, a guard bandwidth W, and a noise level Pnoise, where NF is a noise figure and G is a gain. An IF circuit ( 121-123 ) satisfies PAll<=Pin+G, where PIF is an output level of a BPF ( 123 ). Out-of-band noise levels are reduced to Pnoise by the steep BPF ( 123 ). The RF circuit ( 131-138 ) is structured so that noise from a local oscillator circuit ( 134 ) does not surpass noise from the IF circuit ( 121-123 ). Reductions in power consumption are thus realized in addition to guard bandwidth reductions, because of being able to eliminate out-of-band noise from an amplifier ( 138 ) using a low-loss filter ( 140 ) having an attenuation slope s.
|
