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前置usb
基于USB接口的EH4前置放大器检测电路设计
基于USB接口的EH4前置放大器检测电路设计
EH4系统的前置放大器接口在实际操作中容易出现故障,而且前置放大器不具备自检功能,给故障排除带来了很大的困难,为此以PIC16C57单片机和LM339电压比较器为核心设计了前置放大器的检测电路,通过软硬件的配合来实现实时操作时出现的故障排除,利用广泛应用的USB接口与前置放大器相连接可以方便地使用该检测系统。实践证明该系统可以及时、方便地检测出各个接口的状态,同时具有体积小、便于携带,运行速度快等特点。
USB协会标准
USB 2.0 Specification Engineering Change Notice (ECN) #1: Mini-B connector Date: 10/20/2000 Reason for ECN: The USB 2.0 specified device-side connector – the B connector – is too large for use with a new generation of handheld and mobile devices, e.g., cell phones which would benefit from connectivity to the PC. This ECN incorporates a specification of a device-side mini connector (hereafter r
