| 摘要 |
PURPOSE:To make both transmission level from a speaker in the originate mode and a transmission level of a speaker in the answer mode proper by providing an originate mode amplifier and an answer mode amplifier. CONSTITUTION:A modulator 16 and a band pass filter 17 are changed over so as to be operated at a low frequency band by a control signal 27 in the originate mode at first. Thus, a transmission data fed from a data terminal device 29 to the modulator 16 goes to an FSK signal and after the signal is subject to band limit by the band pass filter 17, the signal is fed to the originate mode amplifier 20 through an analog switch 18. On the other hand, the FSK signal outputted from the band pass filter 17 in the answer mode is fed to the answer mode amplifier 21 through an analog switch 19. |
