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  • EEVblog #470 – Agilent N9344C 20GHz Spectrum Analyser Teardown

    Posted on May 15th, 2013 EEVblog 18 comments


    What’s inside an $18K 20GHz handheld spectrum analyser?
    Rigol DSA815 teardown
    Tektronix MDO4000 teardown

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    • Jonas

      No mailbag monday? :(
      Anyway, I’d prefer more consumer electronics repairs, but this was interesting as well!

    • Jay

      What’s All This Microwave Voodoo Stuff, Anyhow?

      My god, Dave, that was amazing and fascinating. I think I watched the entire video with my eyes bugged out and my jaw dropped, thinking, “This is too obviously directly reverse-engineered from a crashed alien spacecraft.”

      Many thanks to the people at Agilent for sending you this, and giving permission for the teardown.

      Agilent +10, Tektronix 0, for this round.

    • Chris

      I could be wrong, but the access-hole at 41:00 looks to me like a venting-hole to get the board through the soldering-process

    • JoseDias

      it can be Chris, but i also think that it can be anykind of testpoint.

      • Franck

        testpoints are named ! TPx TPy …

        and nothing to test ‘inside’ a non serviceable circuit.

        • JoseDias

          Thanks

    • tchicago

      Did you put all this back together? Or it went straight to your electronics scrap bin? ;)

    • ossi

      Well, i think most people who thought they were good at High-Frequency stuff are pretty disappointed by now.

      At least was brought back to earth for the next few weeks.

      Impressive Video, thanks Dave

      • Laurens

        I’m not that impressed – almost all that stuff is COTS ICs. I’ve done similar designs myself.

        34:23 inductor
        35:12 diode ring mixer (actually used that model a few times followed by some amplifiers (not oscillators!)

        38:15 amplifier
        47:00 microstrip directional coupler
        48:50 mixer and hairpin filters, board looks like FR4, so freq < ~2GHz

    • Worf

      I’m betting that SD card slot was an alternative boot mechanism for the main processor. Basically you put the OS on that and it’ll load up from there instead of the eMMC on the board. Useful for testing or development, and since it’s an $18,000 board, no sense in saving the pennies by not having it – it can be used for debug.

      • http://www.eevblog.com EEVblog

        Yep, very likely.

    • Skye

      When I saw the vent hole being uncovered, my stomach lurched. My first thought was that you had just unsealed a nitrogen purged chamber. Humidity inside those cans may need to be controlled. Lots of equipment I work on is purged for humidity control, although the seals are not normaly copper foil tape.

    • Martin

      Pornographic stuff for all the microwave afficionados like me; well done and thanks for your efforts. Keep going!

      Best regards,
      Martin

    • Ed

      Great teardown!

      Wonder if for fun, you could have hooked up your frequency generator to some of those PCB filter patterns and look on an oscilloscope to see what effect they had to the signal.

      So we might see modulation and filtering of frequencies in some ranges and none at others. That could be a nice Fundamental Friday video.

    • marcin

      Dave
      Will it be feasible to get you to test analyzers that are offered on the http://www.signalhound.com?
      I’m curious to compare these devices.

    • Flux

      Dave, your videos seem to spread out to the world! Guess where they got the pictures from … ;-)

      https://en.wikipedia.org/wiki/Distributed_element_filter

    • Bronek

      Bump up for Ed’s idea! Dave, hook it up, do some testing and explanation, please:) That wobbling filter at 49:56 – brilliant! Hats off for Agilent RF team.

    • http://ledshield.wordpress.com Peter Jakobs

      HF like that isn’t real. During the time I was at the Uni (digital electronics), I always thought anything in and beyond the UHF radio frequency range was HF, then processor designs got to that range and passed it. I still think that people dealing with GHz frequencies are a different breed. Probably from a different planet even.