论文部分内容阅读
(四)键控频标形成图6是键控频标单元电原理图.形成29MHz,30.5MHz,38.5MHz三个键控频标的晶体振荡器,调制器电路形式是完全一样的.图6中5BG_1是晶振级,晶体5SJT_1接在5BG_1集电极和基极之间,等效为电感,改变5C_1及5C_4即可改变反馈量,是电容三点式晶体振荡器.5BG_2是键控脉冲调制级,键控脉冲A、B、C未来到时,5BG_2无偏置,不导通,当负的键控脉冲A来到时,将打开5BG_2使29MHz晶振信号通过,这就使得晶振信号嵌入键控脉冲A形成键控脉冲频标A.
(D) key frequency standard formation Figure 6 is a key frequency control unit cell schematic to form 29MHz, 30.5MHz, 38.5MHz three key frequency crystal oscillator, the modulator circuit is exactly the same form in Figure 6 5BG_1 is the crystal level, the crystal 5SJT_1 is connected between the collector and the base of 5BG_1, which is equivalent to the inductance, 5C_1 and 5C_4 can be changed to change the feedback value, which is a three-point capacitance crystal oscillator. 5BG_2 is a key pulse modulation level, When pulses A, B, and C arrive in the future, 5BG_2 is unbiased and non-conductive. When negative keying pulse A arrives, 5BG_2 will be turned on to allow the 29 MHz crystal signal to pass. This causes the crystal oscillator signal to be embedded in the key pulse A Key pulse frequency standard