请教：RF接收用频率合成器的频率

koukei

请教：
1. Mixer需要2.4GHz的本振频率。频率合成器采用2.4GHz 的LC VCO，还是采用4.8GHz的LC VCO, 经CML二分频得到2.4GHz的本振频率。哪种方案更好。
2. LC VCO输出是比较标准的正弦波，经CML二分频后，波形明显失真。所以2.4GHz的LC VCO经简单的buffer输出给Mixer, 波形为比较标准的正弦波。而4.8GHz CML二分频后，2.4G波形失真明显. 是否说明经过二分频这种方案不好？

谢谢！

uwb11n

1) if you are using quadrature mixer, it is better to have 4.8G L, with /2, you can get very accurate quadrature phase.
2) if you are using switching mixer, you don;t need perfect sinusoidal wave.

rayengine

I prefer step-up by using low-frequency e.g 2.4G/3 = 800MHz and then extract its harmonics.

tomatoes3

有待高手解决.可惜我是菜鸟

cqmyg5

原帖由 rayengine 于 2009-5-24 19:54 发表

                               
登录/注册后可看大图

I prefer step-up by using low-frequency e.g 2.4G/3 = 800MHz and then extract its harmonics.

这个三倍频怎么做啊？