Patent ID: 6952566

Claim:
A transmission circuit characterized by comprising: first and second amplification means ( 1 , 2 ) for independently amplifying input signals in different transmission frequency bands, said first amplification means ( 1 ) in an ON state producing an unnecessary radiant wave in a frequency band substantially coinciding with a transmission frequency band of said second amplification means ( 2 ) in an OFF state; first filter means ( 4 ) for extracting a component in the same frequency band as that of an unnecessary radiant wave leaking out from said second amplification means during operation of said first amplification means; phase adjusting means ( 5 ) for adjusting a phase of an output signal from said first filter means such that the phase of the output signal from said first filter means becomes opposite to that of an unnecessary radiant wave in an output signal from said first amplification means; and signal combining means ( 6 ) for combining an output signal from said phase adjusting means with the output signal from said first amplification means.