| 摘要 |
PURPOSE:To prevent occurrence of the noise at the carrier circuit by setting the frequency the attenuation amount of which becomes minimum close to 6kHz through the preemphasis and then increasing the attenuation amount again near 10kHz along with use of the deempahsis featuring the attenuation amount corresponding. CONSTITUTION:In the carrier circuit in which the pilot signal is inserted to the area near 10kHz equivalent to the high frequency region of the transmission band, the frequency the attenuation amount of which becomes minimum is shifted from the area near 10kHz to 6kHz through the preemphasis. And the attenuation amount is increased again at the area near 10kHz, and at the same time the deemphasis featuring the corresponding attenuation amount is used. Thus the pilot signal's amplification can be lowered to give no overload to the circuit. As a result, the combination is possible in use with the compandor, thus preventing occurrence of the noise at the carrier circuit. |
