| 摘要 |
PROBLEM TO BE SOLVED: To set the characteristic of a speech signal easy to hear for a hard hearing person by filtering a sound signal to a prescribed frequency characteristic with a range filter and boosting the output level into more than the fixed level. SOLUTION: A range filter 8 gives filtering so as to make the frequency characteristic of the speech signal SS easy to hear for hard hearing persons and on the other hand, an amplification control circuit 9 boosts this filtering output to be more than a fixed level. Namely a speech signal on a low frequency area, which is difficult to hear for hard heating persons, is attenuated by the range filter 8 and a signal level on a high frequency range is intensified by the part of the attenuated signal power to obtain voice output easy to hear for hard hearing persons. In this case, the total sum of signal electric power from the low frequency range to the high frequency range is equal to that at the time of a flat output characteristic so that signal distortion is not generated and the articulation of sound output is not deteriorated at an amplifying output part 10. |
