| 摘要 |
<p>PURPOSE:To improve the system modulating a data signal with the frequency lower than voice band frequency during the communication through speech of digital telephone set or the like. CONSTITUTION:To reduce the creeping of the modulation carrier output frequency of the transmitter to the receiver, the reference frequency is applied to a first station origination frequency synthesizer 20 of the receiver from a single reference oscillator 10, and the output frequency from a second station origination frequency synthesizer 30 of the receiver modulated by a DATA signal is applied to the second station origination and a transmission frequency synthesizer 40.</p> |
