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I/Q (Inphase and quadrature) demodulation circuit

  1. May 14, 2007 #1
    Hi guys

    I want to build a I/Q demodulation circuit...operate at 20MHz....does anyone have any experience on building this circuit in a similar frequency range? what kind of opamp + mixer shall I go for? There are too many parts I don't even know where to start from....

    I hav browsed through the Analog Device website and seems like there is an AD8333 chip that can do the trick for me...but the problem is that the size of the chip is extremely small...(5mm x 5mm)...and I don't know how to put that on a PCB....

    here is the link to the AD8333 chip: http://www.analog.com/en/prod/0,28...8333,00.html

  2. jcsd
  3. May 14, 2007 #2
    Yea those chips are even smaller than SMT, and can only be soldered with robotic machines on an assembly line. As the industry pushed the envelope with digital demodulation, small chips are very common.

    But for 20 MHz, you could cook up small demodulator using a split LO by 90 degrees and feed them to two mixers whose RF input is evenly split. The IF's would need to be hooked up to two ADC's. Then rest is coding on an MCU or what not.
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