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发表于 2011-8-2 10:00:36
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回复【9楼】syaoraner
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楼主,您好,小弟最近在看PT2262的datasheet,在datasheet里面有一处疑问:
出现在第七页:
"OSCILLATOR
The Oscillator Frequency for the IR Type of Operation is twice the carrier frequency. Thus, the
oscillator frequency should be kept at 76 KHz. A 430K ~ 560KΩ oscillator resistor between OSC 1 and
OSC 2 pins is recommended. It should be noted that the carrier is a 50% duty cycle frequency. "
为什么振荡频率为载波频率的两倍,如果是射频模式那个振荡模式也要符合这条件吗?
(datasheet里面说:OSC1、OSC2两端的电阻决定振荡频率)
所以推荐红外发射的时候的电阻为430K-560K,可是我接了1M的电阻也会发出40K的信号(我用我51开发板板上的只接受40K红外载波的接收头,发现接收头输出端出现低电平,这应该可以说明有40K的载波发出吧)
这个是datasheet的链接:
http://www.ourdev.cn/bbs/bbs_content.jsp?bbs_sn=4922602&bbs_page_no=1&search_mode=3&search_text=Helloeveryon&bbs_id=9999 |
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