在NTSC制中副载波的频率为() ["A、3.58MHz","B、4.25MHz","C、4.406MHz","D、4.43MHz"]
为了实现频谱交错,NTSC制采用()方法选择副载波 ["A、1/4行频间置","B、半行频间置","C、行频间置","D、3.58兆间置"]
在PAL制中副载波的频率为() ["A、4.25MHz","B、4.43MHz","C、4.406MHz","D、3.58MHz"]
氮的总平衡
申请成为禁毒志愿者的年龄要求() ["A、没要求 ","B、14周岁以上 ","C、16周岁以上 ","D、18周岁以上"]
氮的正平衡