这个一个关于红外接电路设计问题:DUT
发出红外光,我们设计红外接收电路。 目前收集的红外发射电路设计的信息如下:1. DUT使用的红外发射二极管型号:SFH4725S.(发射驱动电路没有)。接收电路要求(客户提出)如下:1. Thecircuit must transmit a 38.4kHz square wave with good signal shape
2. Ideallysignals at their destination will have a smooth monotonic edge with noovershoot. For a 50% duty cycle clock, a general3.
ruleof thumb is to be high at least 1/3 of the period and low at least 1/3 of theperiod. This leaves at most another 1/3 of the period to spend in transition. 我目前设计了一个电路:使用HS0038B这个红外接收头。但是客户不同意。客户不同意的原因如下:as the below block diagram shows, in the HS0038 there is avariable-gain amplifier with AGC which allows the circuit to work with very lowirradiance. This means that the DUT emitter could be mis-assembled or evenblocked, and we would still detect the signal. I asked for a solution to thelow-bandwidth problem I cited, that would be of the emitter-follower type。现在寻找大家帮助,怎么解决这个问题。
补充内容 (2016-1-30 14:43):
虽然这个不是最佳答案,但是感谢jack的回复。现在用TC7SH17F已经验证成功了。
或许客户要的是 TSOP38338 或 TSOP38538,而不是 TSOP38138 (或 HS0038)。
不是红外发射的编码格式,那是软件的问题。所谓红外接收的规范是指接收电路的规范。如果客户没有这个规范,建议 LZ 通过和客户的沟通,搞清楚这个规范(自己定义出来)。
仔细阅读 1# 客户的话,貌似是被干扰的问题:
... This means that the DUT emitter could be mis-assembled or even blocked, and we would still detect the signal...
所以,关键的问题是搞清楚客户究竟要的是什么?所谓的 low-bandwidth problem 究竟是什么问题?这个问题搞清楚了就容易下手了。
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