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Author Topic: Inside the GPX-4500 andGPX-5000  (Read 2295 times)

woody

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Inside the GPX-4500 andGPX-5000
« on: December 20, 2016, 09:18:39 pm »
Has anyone ever wondered just how they work?  These detectors have 2 main hearts, a CLPD, a complex logic device that is located right next to the Hitachi processor ic, these 2 devices control the timing for various tx and rx functions and general housekeeping as like controlling the electronics when switches are changed. The input stake is much the same as the GP series except they are using a reverse biased n channel mosfet as the second device in the tx on voltage and back emf blocking, a dual gate mosfet is used to hold the input ad797 inputs to ground when not in receive mode. The only difference is that in previous detectors the mosfets were connected to ground but now there are 1k resistors in series to ground. Next in line are the usual bank of 4053 switches and as a slight departure from old designs 10 sets of dual opamps. power supply and feedback is much the same as the old GP design.