| 摘要 |
<p>A loudspeaking telephone includes first level control means (4) positioned on a transmitting path, second level control means positioned on a receiving path (11), frequency shifting means provided on at least one of the transmitting (3) and receiving (12) paths for shifting frequencies of at least one of a transmitting path signal and frequencies of a receiving path signal, and level comparator means (6) for comparing the levels of the transmitting path signal and the receiving path signal to control the first and second level control means.</p> |
