BALANCE NETWORK OF KEY PHON SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a balance network in which speech sensitivity, side tone level or the like can easily be adjusted into a desired state. SOLUTION: An inverse phase output TX INVER of an operational amplifier U2 on a transmission path is sent through a feedback signal level control circuit 10 to an operational amplifier U3 on a reception path and matched with a feedback signal TX FEED to be a side tone source. Thus, respective circuit parameters are adjusted, so that speech sensitivity and the suppression degree of side tone can easily be decided.