Part 2 of the Tektronix MDO4000 Mixed Domain Oscilloscope review. This time, a world exclusive tear down. What magic lurks inside the die-cast shielded RF spectrum analyzer circuitry?
10:55 well the fan is pretty much skimped in that it doesn't have a dust filter and it's a fairly old design with not a lot of blades. Meaning the fan is going to be ridiculously loud for the amount of air moved, as opposed to modern fans that have multiple folds more blades in different orientations to minimize sound production
The circuitry under the diecast shield appears to mostly be signal conditioning (attenuators and gain), split into three basic paths for the (approximately) 0-2 GHz, 1-3 GHz, and 2-3 GHz input ranges. The first (and probably only) local oscillator is a $10 ADF4350 integrated VCO/PLL chip, which can also be seen in the $900 Signal Hound spectrum analyzer. That explains why the phase noise specs between the two units are so similar, I'm guessing.
@omgitschrislol The ones you are seeing in fry's are an order of magnitude less performance than this scope. You have to compare apples-to-apples. Price goes up very quickly with increasing bandwidth. No, I did not keep it.
The real state of the art engineering in this amazing instrument is NOT in the RF section you are all drooling over. That looks like pretty basic RF design to me, i.e. it's quite easy to trace the circuit paths and see what is going on. It really is just a basic two path RF downconverter (plus baseband path) and I've been designing RF downconverters in the GHz region for over 20 years. The real state of the art engineering in that scope is in the digital back end AFTER the RF.
The long cigar shaped thing with ferrites looks like a broadband balun to me. Probably 50 ohms input with two 25 ohm balanced outputs. i.e. this device will produce two output traces 180deg out of phase which is what a differentially driven ADC needs. There looks to be a pair of buffer amps plus SMD alias filter after the balun outputs. I could have a reasonable attempt at identifying the whole RF circuit including a lot of the parts but it's hard to be sure from a slightly fuzzy video.
@omgitschrislol High performance and high frequency RF and scope frond ends are not cheap (or easy), they use lost of specialised and exotic custom components. This is why only a select few scope manufacturers in the world are able to do 1GHz+ bandwidth scopes for example. These components are orders of magnitude more expensive than components in say a 50MHz scope. Someone on the forum mentioned the RF relay used alone is $50 on it's own or something.
@EEVblog Oh ok I understand. I want to be an Electrical Engineer so all the information I can get on tools and test equepment and other education is very welcome.
@omgitschrislol There is nothing new about expensive exotic high performance test gear like this. You can pay over $100K for a top end performance scope. Volumes are low too of course. If OneHungLow in china could sell a 1GHz+ scope for $1K-$2, they would. Even a "cheap" brand like Rigol sell their 1GHz scope for $10K.
Does anybody know the location of UART pins? My mdo4054b-3 sometimes won't boot up (hangs on logo screen), so I wanted to see boot log and understand where it gets stuck..
They probaly saw your letting out the smoke of the $12,000 agilent one and was afraid the same thign might happen to theirs :P (not saying you actually did anything to the agilent one, just commenting)
@guitarbridgecleaner You're not including the cost of engineering, hardware engineering, software engineering, custom chips (with obvious payment for consulting services). They are obviously not going to be selling millions of these things. They aren't gearing this to home/hobby users, it's a piece of pro equipment probably going to be bought in very low quantities to large firms.
@omgitschrislol The ones you are seeing in fry's are an order of magnitude less performance than this scope. You have to compare apples-to-apples. Price goes up very quickly with increasing bandwidth. No, I did not keep it.
