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    MultiStage FrontEnd Receiver Desing Using BF998

    hi,

    I want to design a sensitive 3 stage receiver circuit for 40 MHz using BF998. Very narrow bandwidth (39-41MHZ) and maximum attenuation is required out of the band.

    I need help in the following steps

    Input filter design (type and order)
    Biasing the BF998
    impedance matching at input side .
    Interstate matching
    Output matching to NE612 mixer ic.

    I can simulate the design in ADS 2009.

    Regards

    •   Alt8th June 2018, 07:42

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    Re: MultiStage FrontEnd Receiver Desing Using BF998

    If you attempt to catch a certain degree of sensitivity, I recommend you to consider "Noise Matching" that will give you lower Noise Figure from that amplifier.
    If the first stage of the chain is a Filter, the Insertion Loss of this filter will contribute directly into Noise Figure of the system so the first stage shouldn't have lossy elements.( the frequency is low so high quality compact components should be used to prevent high losses).


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    •   Alt8th June 2018, 20:44

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    Re: MultiStage FrontEnd Receiver Desing Using BF998

    Thanks for reply.

    What is the sensitivity of NE602 or NE612 mixer ic? Can it receive -90dbm signal without any per-amplifier stage?



    •   Alt13th June 2018, 06:43

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    Re: MultiStage FrontEnd Receiver Desing Using BF998

    Quote Originally Posted by adnan012 View Post
    Thanks for reply.

    What is the sensitivity of NE602 or NE612 mixer ic? Can it receive -90dbm signal without any per-amplifier stage?
    I don't know and it depends on your bandwidth.But -90 dBm is pretty low and a LNA ought to be used.



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