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7.振铃电路主机振铃电路是将市话外线输入的90V25Hz 的振铃信号转换成射频信号后供手机接收,产生振铃。在无绳电话机中,振铃电路一般采用门电路,该电路结构简单,容易引振,频率范围广。图13(见上期)即是采用4001的(11)～(13)脚和 CD4069①、②脚门电路组成频率为几千 Hz 的振荡器,和4011的⑧～⑩脚、CD4069的③～⑥脚门电路等组成近似相同频率的振荡器,并用频率较低的信号去调制频率较高的信号,使输出的振铃音比单一频率的好听。在呼叫状态,因只有
7. Ringing circuit The host ringing circuit is the external incoming 90V25Hz ringing signal into a radio signal for the phone to receive, ringing. In cordless phones, the ringing circuit generally adopts a gate circuit. The circuit has a simple structure and is easy to lead a vibration and has a wide frequency range. Figure 13 (see the previous issue) is the use of 4001 (11) ~ (13) feet and CD4069 ①, ② foot gate circuit frequency of several thousand Hz oscillator, and ⑧ ~ ⑩ 4011 foot, CD4069 ③ ~ ⑥ foot Gate circuits and other components of approximately the same frequency of the oscillator, and use the lower frequency signal to modulate the higher frequency signal, the output of the ring tone sound better than a single frequency. In the call state, because only