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- čas přidán 22. 07. 2018
- A step-by-step walk-though of a typical modern low cost 3GHz "All Digital IF" spectrum Analyser design.
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Yes! I really enjoyed this style.
I dont usually bother commenting on videos, but this one is filled with so much good information that I have to say thank you!
I really like this enhanced teardown/explanation video. Well worth the extra effort.
Dave, I am 728% American but after watching a video from you, occasionally I find myself saying, "hi," to someone but in your Australian accent. It throws people off but it also means I love you stuff.
A real Aussie says "G'day" ;-)
A real Aussie says ''Oi!''
This type of teardown is way better I guess. Appriciated. I study EE and specialized in Microwave circuits. I find these teardowns extremly interesting. Thank you :D
Great job Dave the visual of the various modules for me made this easier to follow.
Good job based on your experience, knowledge and research. Thank you :)
Awesome!
This is fantastic, this style is definitely worth the effort for something as complex as this circuit was, I think! Thanks
Outstanding summary Dave. Fascinating - thanks!
This was awesome, I'd love to see more of these types of videos!
Thanks for the vid Dave. I can see you've put tonnes of effort into researching and making this video (and all your others too). Late nights, I suppose? Really great content. Always have to click fast on your vids!
I tweeted about it last night, I was (as usual) the last in the building.
This was a really good presentation. I liked it!!
I love this Dave. Keep them comming.
Amazing video! Thank you! I liked this style a lot and would enjoy if you made it more often!
Learned a lot, thanks Dave. I enjoyed the style of video.
Yeah, I really enjoyed watching this video. Awesome work!
Nice work for a complex design. Keep up the good work!
I enjoyed this video immensely.
Dave, great stuff. thanks.
Signal Path does alot of RF stuff, but man the editing on this video is really notch and nicely done easy to follow really great video.
Thank you so much again for this awesome video
Excellent walk through !
I like this type of teardown, more of it please. :)
Simple and clear, good job.
Loved this! Those high frequency filters were super interesting to see. Keep this up if you can.
Brilliant style! Really appreciate :-)
great video, thank you very much
It works for me,thanks and not seen such high speed processing carried out.
This was fantastic!
I like that new style!
amazing .... well done .. thank you very much
GOOD stuff!! Thank you!
Very nice and very informative!
This is excellent. I wish you did more in-depth videos like this.
Yes I like the way you have done this Walk-through, compared to the previous one.
cool vid! much better than a teardown.
Good job! Thank you.
I like your tear downs main reason i watch this is mail bag and tear downs seeing inside expensive stuff i would never get to take apart myself is awesome. And i like the off the cuff style of the old ones but this wasn't bad either.
I liked it very much!
More of these videos please!
Useful video
Nice video. I was just reading my good old print copy of AN150 last week.
Just in case Dave's humor is confusing anyone, Daylight starts at 400 Terrahertz (10^14)
It's not the humor that's confusing me - it's the failure to explain anything! Seriously, if you already understand what he means by all these numbers and jargon, then what are you learning?
JL Software, it's like understanding the rules of a game and then having somebody walk you through a particular game strategy. You can understand electronics and RF basics but still get something out of an architecture walkthrough.
still dont get it.. derp
what rules? are youse talking about Laplace transforms? Dave I would love to see you do a design engineer channel. But having said that if you did it properly it may well bore a lot of people to death and have math going way over their heads. Could you have a frank discussion about becoming a design engineer, what expectations should i have post uni.. Ive had people say you only learn simple stuff, others say its easy!! in ref to circuit design. I know self learning is a key, what do you think uncle Dave?
There really is only one way to go. Get the fundamentals firmly fixed and then specialise. What is your favourite field? Once you understand how things work, things will obviously become easier and you will not ask such questions, you will be thinking of other stuff. Dave has his areas of strengths and weaknesses too, he would be the first to admit he doesn't know everything.
So just start at the beginning and things will fall into place.
cheers, Im interested in control systems at the moment
Excelent. Thanks a lot.
I enjoyed it and appreciated the education. Wouldn't mind similar for other gear.
awesome !!!!
Thanks for the great video, So what are those golden strips for?
Many thanks for the review, hello from Russia
Hey Dave,
At 19:54 The inductors L105, L102, L103 and other capacitors were not populated meaning the optional bandpass filter upgrade might need a slight hardware upgrade.
Thanks
That's great! :D
Pretty nicely done, I bet it is quite labour intensive to edit. You could easily spend a day or so editing this sequence and tweaking it untill it’s just perfect. There is a lot of attention to detail here.
Can you include the Keysight link you mentioned :)
Can someone explain me the problem with "dead bands". i guess cos (w - wl) will turn 0 eventually tho i dont understand how mixing it up first will help. if anyones knows a link i would be happy if you could share it.
15:13 What is tipical bandwidth of that filter? I assume its max RBW depended?
What IC are they using for the preamp?
The sentence "It's at this point that the this "All digital IF" analyzer become digital" hit my assburger so hard you can see the compton scattering from mars. For the love of god, think about us anal retentive types before clicking 'render' thank you so very much!
Dave, please do another video to show how the spectrum is mixed in with all of these different oscillator frequencies, how the waveforms would look like when fed into the ADC, how it'd look like if each of those stags were removed to show why they are needed. I don't understand how the spectrum is extracted using an ADC. Thanks
Should that not be a Tayloe mixer with a clock of 44mhz driving a 74AC74 to generate the clocks to drive a 74HC152 with a balanced input(BQSD) to generate I/Q which can drive the IFFT to allow as to get a spectrum display.
(BQSD=Balanced Quadrature Sampling Detector)
Dammit I only just rewatched #892, now I'll have to watch this one for the "added niceties"
Why is the solder mask cut like that?
For people interested in this, there is another channel that tears down and repairs such instruments while explaining The Signal Path.
Good video Dave. RF is bizarre stuff. GHz RF is witch-doctor level bizarre. My head hurts.
While I can usually easily understand and follow most of your videos this one is all Greek to me. Time to read theory about this.
Going to be honest, I prefer the ad-hoc, behind the camera, plastic pointer versions. Bit too powerpointy for me, this. Gives me the glaze over.
Why are my ears wet? Ohh its because my brain melted. Haha don't dumb these videos down, I just need to learn more
I like this. I wish you'd do a little more fundamental 101 kinda stuff within these kinds of videos. Maybe you could just briefly point out something simple that would help the hobbyists learn. Most of this is still way way over my head. Things like the embedded elements are obviously foriegn, but even things like the "SPDT" switching elements are foriegn to me as well. I don't know the broad spectrum applications for such things. Every little bit helps ;)
Thanks for the upload.
-Jake
9:00 what is that white thing marked AZ?? 😐
I miss the poker. A stick at the end of your fingers is more accurate and easier, plus you dont need to describe "The part with the 20 written on it"
But every now ant then this is interesting. I guess it has almost educational quality this way.
Dc to daylight :)) love you Dave
(: Nice Dave Saudi Arabia over here (:
Great! I feel like this video was a major PITA to edit.
I'm sure Ḫattušili would be proud to see his kingdom's name living on like that, if a little confused!
DEFs are so cool-looking.
Please someone help! This has always freaked me out and I have never found a good answer for it. If you have a signal with relatively high content in it, say 2 or 3 gig, how the hell can you mix that with another signal and down to the range of the ADC and still expect to see the high frequency content?! I have watched nearly all the vids from Shahriar at The Signal Path, and the ones Dave does, and I just cannot get my head around how this works. If I mix say a 100Hz sine with a 1kHz sine, then I get the 1k 'riding' on the 100. I couldn't then expect to put that through say a 500Hz ADC and see the 1k info - could I? Then how does it happen with these higher frequencies? There is something I am badly missing here and I would love it if someone could put me right. Cheers - Andre from Sydney. (Edit: look at the graphic at 17:15 - 3.6Ghz in, eventually mixed down to 22.5Mhz - and the ADC still gets to see all the 3.6GHz content?! What mixing magic is this?!)
Sorry i can't tell you, because it is top secret....LoL
Thanks bog... very helpful..not!
The mixers produce the sum and the difference of the input frequencies. In the figure, the filter blocks are only passing the difference. The idea is there is modulation on the (for example) 3Ghz signal. That modulation "spreads" the 3Ghz carrier +/- 10 Mhz say (again for example). Using mixers, the carrier is shifted down to something that can be processed digitally (e.g. 22 Mhz). Think of the carrier as the frequency of a tuning dial on an old analog radio. The carrier frequency does not change the sound of the music, and the radio will play it whether the song is broadcast at 680Khz or 1.6Mhz.
One issue I see is that you seem confuse mixing/downconverting with summation. I'm going to use some simplifications, but it should help give the gist of how this works.
It's usually easiest to picture what the mixer does in the frequency domain. It allows you to have two signals interact so that you get resulting signals at the sum and difference of their frequencies. This allows you to shift a signal along the frequency axis. You still are bandwidth limited by your ADC, so what you do is look at the higher frequency content in chunks i.e. if you have 50MHz of ADC bandwidth, you have to take ~20 measurements to look at everything from 1GHz-2GHz
Another thing that may help you understand is sort of reversing your '1k riding on 100' example. Typically in communications it is the opposite. You have a low frequency carried by a high frequency. In something like amplitude modulation you are concerned with the low frequency variation (envelope) of the high frequency signal, not in the instantaneous value of the high frequency signal. The information of the signal is carried in the envelope .
Thanks Nukes & Cliff. Let me re-read your replies a few times and digest... i totally get AM and modulation etc and didnt know we were dealing with similar concepts..also it seems from what you say that an ADC having '20MHz' has more to to with bandwidth than highest freq...? Let me think and read this and other sources again. It's one of those things where i want an intuitive understanding of the concepts rather than "this just happens". Thanks again!
I recognized the SSA from the screenshot as I just watched the teardown yesterday...this messed with my head
Oh, that would suck, yeah. Not much extra if you've watched it all the way through before.
I'm still calling RF black magic. :V
interesting.
Winner Winner Chicken Dinner! @22:43 #PUBG
I hate that 3 wave filter symbol. The 3 waves can not express the complexity that can be shown by drawing the passband shape.
Agreed
The thumbnail to this video looks a LOT like the map for Legend of Zelda. (NES version)
I thought the thumbnail was an overworld map from the Legend of Zelda.
Justin Mohns Its a piece from the Roswell UFO.
wha... how does that bowtie thing work? (oh, about 15 min through ya tell me I can google it. ok. one day, maybe...)
I made it to 1 minute and 55 seconds and was totally lost. And I really, really wanted to learn how a 50 ohm impedance was made. Shit.
it is made by impeding the load down to 50 ohms lol.
Hah - I've been hanging in there for years now.
Very funny. Impedance is not the same as resistance. So you can't just put a 50-ohm resistor there. So how do you wire a "50-ohm input impedance?" I don't understand SOT-23 or "switch in a 50-ohm load impedance" or any of the other gibberish he considers teaching.
JL Software You’re not alone.
I'll stay subscribed but I can’t watch any more of this right now - maximum frustration. And to think I have a Amateur Extra radio license. What's the point of flying through a circuit board and waving around a bunch of components and saying "that's the XXX"? Or worse, the oft-repeated "not a whole lot there, that's all she wrote, not much there", etc.
What do you mean by "switches?" Do you mean transistors, or actual physical switches? Be precise. And point to what you are talking about.
First
That's 4! 😁👍🏻
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