#60: Basics of Phase Locked Loop Circuits and Frequency Synthesis

This tutorial style video presents the basics of Phase Locked Loop circuits. A basic block diagram of a PLL is shown, and the individual blocks are discussed. The Voltage Controlled Oscillator (VCO) is described and demonstrated. The two basic types of Phase Comparators/Detectors, often referred to as Type I and Type II, are described and demonstrated. Then, the overall operation of the PLL is demonstrated. The addition of a simple divide-by-2 is shown, and how this is used to double the output frequency of the VCO, the basis for frequency synthesis. Finally, the operation of the phase detectors is demonstrated a little further by purposely injecting an offset into the feedback loop to show how the loop compensates for this offset. A copy of the notes in this video can be found here:
www.qsl.net/w/w...

[@douggale5962]

This is the most informative electronics channel I have found yet. Thanks!

[@unlokia]

This and "Mr Carlson's Lab" are absolute gems of information. 💎

[@SuburbanDon]

He's good isn't he ?

[@RadioWhisperer]

Another straight forward explanation of a reasonably complex topic. I have learned more from your videos than I did when I got my degree back in '81. Great job as always, and thank you for what you do. I don't even know how to begin to thank you and express how much I appreciate the time and effort you put into this!

[@asalgolmanesh7817]

There is no word that I can express my appreciate to you

[@gregorymccoy6797]

Hands down the best PLL explanation I have seen. Thank you for such a great video.

[@Zurh1994]

Thank you, you saved me. I didn't know ANYTHING about PLLs and now I think I understand in just 20 min! THANK YOU

[@VoidHalo]

I've found a lot of topics in electronics are a lot easier than they seem. Even the math.

[@MythCraft00]

Things really start to make sense if the teacher isn’t just throwing formulas at you :) amazing explanation, as always

[@microlatinamicrocontrol1240]

A compact and still very rich concise information. Good teachers as you are gifted people, because there are many smart technicians out there explaining things but a very low percentage of them can make the magic. This means having crystal clear knowledge and the ability to transmit this knowledge with the smallest amount of accurate words. Congratulations ! Greetings from Buenos Aires, Argentina !

[@gerryjamesedwards1227]

This is the fourth or fifth video explanation of the PLL I've watched. Should have come here first, Alan nails it again. It's the difference between "that kind of makes sense" and "Aha! I get it!".

[@tombardier]

This mirrors my thoughts exactly!

[@BrockNanson]

I needed to understand a PLL board I'm trying to adjust and decided to see if you had done a video explaining the basics. Sure enough, here it is! Simple and concise - much, MUCH appreciated!

[@chrisengland5523]

Another excellent video from Alan - again with just the right amount of theory and plenty of oscilloscope waveforms to illustrate what's going on.

[@jhettish]

Thanks for the video. I've been working with synthesized two-way radios since the late 70s. I began my "temporary job" in 1972 so I could go to law school at night. Oddly enough life got in the way and I spent the next 10 years learn my trade before starting my own company. May 1, 2020 marked the 37th anniversary of the founding of my little company. Thus I've had my temporary job for 47 years and at 75 am still working daily. I've been president of my small corporation for the last 37 years but I still identify myself on income tax forms as technician. My jobs in the company are numerous but I enjoy the bench best. My bench job is to fix the unfixable. I often go back to the basics and particularly enjoy your videos. My specialty is primarily RF. Watching this video with my ancient brain will probably cause me to watch it again, possibly multiple times. I tended to get distracted by the presence of a Simpson 260. My young people have to use a auto ranging DVM. I know things where the Simpson 260 is preferable. :-) My ham call (from 1960 to today) is K4WJZ. It is not a vanity call but "hamming" is primarily repairing or modifying ham repeaters. Thanks once again for your videos. John Hettish

[@T7thK]

I remember watching this video just about 10 years ago when I was in Electronics Engineering school. I haven't come across PLL's again, until now. I've come full circle so to speak. This is a timeless explanation of PLL's. Well done sir!

[@m1geo]

I knew absolutely everything in this video. But it was fantastic to watch! How satisfying!

[@TheRealMonnie]

This is the boat I'm in. Love his videos.

[@viswatess]

I became a fan of you. What a way to explain the PLL working principle with live demo. No word to explain. Hats off to you.

[@GregSr]

Excellent tutorial! My training is in Air Force analog flight simulators - non-engineer. As a civilian, back in 1988 my GE television lost its audio. I had to teach myself how a phase lock loop synthesizer worked and used a scope to prove the PLL had died in my TV. It had no analog output to control which channel the audio should be on. I installed a new PLL and all was good. I wish I would have had your video back then. Thanks for posting. Brings back great memories!

[@topquark22]

I am finally starting to understand this. An op-amp seeks to equivalate the voltage of its inputs. A PLL is like an op-amp in the frequency domain, which seeks to equivalate the phase of its inputs. This is the best explanation I have seen. Thank you!

[@w2aew]

Yes - both are examples of negative feedback systems. An op amp is a basic one, a PLL is a more complicated one.

[@Bestietvcute]

Thanks for making this video man very clear and straightforward and very helpful too

[@ufohunter3688]

I miss your back to basics series. They're timeless. I've watched them all and learned so much. Thank you.

[@w2aew]

Are there any topics that you'd like to see a "back to basics" video on?

[@ufohunter3688]

@@w2aew I'd love to know more about filters used on SMPS output filtering, Understanding Op Amp Parameters in a datasheet and what to watch out for, Exotic Op Amps like Chopper Op Amps and their use,... But anything will do. You make videos no one else makes. None of that "Lets make a video about a subject that ten other people have already made a video on KZbin"!

[@billmoran3812]

Alan, the first time I watched this it made sense, but going back and reviewing it, I found the answer for a project I'm building to use WWV to provide clock correction for a 10MHZ frequency standard. It's exactly what I am trying to do. Time to get the breadboard out.

[@walterwinnipeg7350]

Wow, a great explanation video for that 4046 chip! My first electronics engineering job after graduation in the late 1970s was with Burroughs, and I worked on a large mainframe disk drive that used a 4046 PLL circuit to generate a clock signal frequency that was locked to the spinning spindle, on which four 14" diameter disks were mounted. The input reference signal was a once-per-rev pulse from a magnetic sensor. We used a multi-stage divider after the VCO to generate a comparison signal. I did not do any of the design work on that PLL circuitry, although I did troubleshoot quite a few product units that weren't work properly. I do have a couple of those same Motorola MC14046 chips in my IC collection, so one of these days I'll take a close look at the data sheet (in the original printed data book 🙂) and set up a few experiment circuits, just as you've done in this video. There's nothing like "doing the math" on component selection and actually coming up with a circuit that does what it was supposed to do.

[@praveenkumarsingh1436]

This is the best video i have found ever on KZbin for PLL. Thanks a lot..❤

[@DavePKW]

You know I have some basic knowledge of these circuits from school many years ago. However there is nothing like seeing a real world working example of the circuit. That is my favorite thing with your videos. You close the loop on the explanation 🙂. You see what I did there. 73

[@Manticore1960]

Been a few decades since I last had dealings with PLL & frequency sythesis. This video was a great refresher course for me. Everything was explained clearly & concisely. Your "hands on" video is much easier to understand than the pure theory explanation provided by other You Tube videos. Excellent.

[@MickHealey]

You have a brilliant teaching method. This is the second of your videos that I have watched. In both cases, there was a point where I thought "yeah - got it". Once I have 'got it', it becomes something that I understand, so nothing to remember. It's great that you avoid complicated maths, and get straight down to how it works. Once I understand how something works, the maths is much easier.

[@w2aew]

Great - now you only have 336 more videos to go!

[@RamKumar-ms9iq]

very helpful crash course to understand PLLs, thanks

[@EJEuth]

Great explanation, demystifying PLL and showing in practice how (and why) it works, with lab equipment setup that usually is not available for most of us at home. Thank you!

[@mightywombat]

I really appreciate how approachable this video was for me as a non-engineer electronics hobbyist. One suggestion for addressing your tangle of test probes: if you put male pin headers in the breadboard along each side, that will give you tie points into the circuit that you can connect to without obstructing the view.

[@SuperJetjockey]

I always admire the fact that you can take a complex subject and explain it in a clear, easily understood manner.

[@ehsanbadry8878]

This is fantastic, you practically explained my 9 hours theory class on PLL in under 20 minutes. Great video.

[@clytle374]

Thanks for sharing your knowledge, great KZbin channel.

[@yuzhang9904]

I am a EE PhD student. I just want to say you are absolutely brilliant and you help me a lot in understanding those important points from a practical perspective.

[@w2aew]

Thank you for the nice comment, and I'm glad to hear that my video(s) are helpful in your studies. Best of luck with the PhD!

[@yuzhang9904]

@@w2aew Thank you so much!

[@MikeMoretti]

Thanks for this video! It's frickin awesome! I've been trying to figure this stuff out for years and you made it sooooo simple and easy to understand!

[@peterjones3245]

What an absolutely outstanding tutorial. Content and delivery are perfectly balanced. I now understand the use of a type 1 PLL where the incoming signal is RF carrying intelligence so the polarity of the phase comparator is not important. I now feel confident in trying to repair the PLL on my ham radio. Thank you so much.

[@vinnovation447]

I got this class 30 years ago however, I have use the XOR and the LM566 VCO separately. It is now that I see it all together. It has always been there in front of me and now I understand it well. Thanks w2aew.

[@LL-ue3ek]

Great video! Important concepts made easy to understand, clear and to the point. Although these are the basics they are critically important basics only on which can you build complications with confidence! Thank you for the presentation.

[@Paddington2000]

This is definitely the best explanation of a PPL that I've found, thank you.

[@BM-jy6cb]

I've only just come across your channel and have watched 5 videos in a row. Straight to the point. Clear diagrams and explanations. Superb. Thank you. Subscribed!

[@rycable]

That so nice to see real example of pll, not just the written theory. Like the fact the you go step by step.

[@RameshKumar-nn7ds]

Sir great explanation as always ,much appreciated ,thank for the great work

[@chuchan60]

I really enjoyed this video and your explanation and demonstration of the PLL in work was wonderful! You inspired me to want to experiment with an analog PLL circuit someday soon. Thank you for taking the time to make this video and I look forward to watching more of your videos!

[@hyperboogie]

Incredibly informative and well explained. Thank you so much for taking the time to create these videos.

[@NahuelAguilar93]

You are an excelent professor, and if you are not a professor, you should be. Thanks for all your amazing videos.

[@w2aew]

No, I am not a professor. Maybe in my next career. I am an electrical engineer that started in a TV repair show while in high school, spent 25 years as a design engineer, applications engineer, test engineer, validation engineer at various companies. I joined Tektronix as a field applications engineer about 10 years ago.

[@ecniv5700]

Thanks so much for your tutorial. I really can't tell you how much I appreciate this, but your contents have given me job opportunities

[@RanHam]

Thanks. I wanted to learn about phase locked loops, clicked on the first video that came up, and Im glad I did

[@geofftarcha1117]

This was a really excellent video, I learned a lot about Phase Locked Loops and it reaffirmed what I knew before. Thanks!

[@kanagarajpalanivel8271]

Alan,I am a professor of medicine and dean of a medical college interested in electronics.I have watched some of your videos.as always this video on PLL is very straight forward.these kind of practical set up and demo is amazing and makes things black and white.that too after some initial minimal reading,this video makes the theory very clear.Absolutely fantastic.keep going.amidst COVID-19 it is refreshing.being a medicine teacher,I like your way of your teaching much-dr.kanagaraj

[@Amir-kz6yq]

Great video as always, thank you Mr. Wolke.

[@hackercop]

This was a very informative video, far above the low tier educational content on youtube. Have subscribed

[@martinsdundurs9497]

I feel like my Chakras have opened and I made a profound connection with the Universe (of Electronics) after watching this video. Those analog scopes are fantastic.

[@Nermash]

This is the best explanation of PLL I have seen so far!

[@kd1s]

Thank you for the explanation of PLL. It's used in a lot of receivers that I now of and all the videos I've watched make me itch to start experimenting again.

[@MichaelLloyd]

I know it's an older video but I really liked this one. You simplified the mysterious.

[@PYoung2493]

Thanks for taking the time to do such a good video explanation. The extra credit was just excellent!

[@famossfla]

Wonderful explanation of Phase Lock Loop Circuits. Very much appreciated. Thanks very much. Amos

[@BenBilesBB-box]

Thanks, this is a great video, simple and to the point, finally i'm begining to understand how the PLL / phase detector is working :)

[@alocin110]

As always, your vidoes and subject are well explained. The bonus part of this video was really amazing. I love watching your videos. Thank you for sharing. Regards.

[@scottneels2628]

Thank you so much for this. It's answered so many questions I've had for such a long time. I thought I'd never understand but now I do. Thank you especially for the"Extra Credit" bit at the end, it's exactly what I need for my application of this circuit.

[@ArjunaWeerasinghe]

You are my favourite teacher! May you get long life and happiness!!! Love from Asia

[@markday3145]

The description of frequency synthesis was an "Ah ha!" moment for me. Now I have a much better understanding of how a microcontroller can create a rational multiple of some reference frequency (like from a crystal). Another use case I've seen for a PLL is when you have an external data signal with a clock signal embedded (like Group Code Recording for floppy disks), and you need to synchronize the receiver's clock so that you can reliably sample the data at the correct rate.

[@MrOndrejHruska]

Great video, thanks for sharing! I never understood what's going on in a PLL-until now.

[@AldrinAlbano]

WOW! Simpson 260 multi-meter!! I haven't seen those since the 1990s in the US Navy and they were already "ancient"

[@DeeegerD]

I remember hearing about PLL back in the 70's - it was a selling feature. Nobody knew what it was except that it was more precise.

[@respomanify]

Given that they are almost indifferent to internal properties (monotonous VCO and good enough low pass filter) means that they are precise enough even with simplest and cheapest circuits. But probably real reason was that they were trivial to control digitally.

[@dereklaur2154]

Very good explanation. Loved the old analog meters and diagrams

[@Aemilindore]

Thank you so much. By far the most practical way to learn the functionality of a PLL. Lovely work. Lovely thinking! Thank you so much and hats off to you!

[@sdejesus13]

Excellent description of a commonly misunderstood circuit. Thank you very much!

[@NumosG]

Finally! Always wondered, how FPGAs were able to upscale a given clock signal. Now it all makes sense. Thanks!

[@bryanwa7prc647]

Alan, Other than a few mispeaks, I found this very good. It reminded me of a project I built in the 1980s - a stereo FM generator from an article in Radio-Electronics. The L/C oscillators drifted horribly. I used a 74HC297 phase detector w/ a 4059 divide by N to hit each RF channel. My reference was a 10 MHz crystal. It seemed to exceed the stability standard required for FM BC transmitters. The stereo L/C oscillator generator produced 76 KHz and divided by 2 and 4 to get 38 KHz and 19 KHz. I scrapped that, and used a 74HC4060 oscillator/divider w/ a 9.728 MHz "rock" and picked the /256 and /512 outputs to get 38 & 19 KHz. Tuned circuits were adjusted for least phase difference (greatest stereo separation). 73, Bryan WA7PRC

[@jiaweitang3994]

sincerely thanks for your sharing!!! pll has puzzled me for a really long time, and your video is so informative! thanks!

[@Pillowcase]

this is amazing. The more I watch your tutorials and other EE videos like this - the more I realize that even I can understand this analog (well, and digital) black-magic :)

[@cynikalX]

...wow! the quality of your videos has NEVER dissappointed me and this particular one is a GEM :-) seriously, they should just put a link to this/your youtube video in that data sheet :P

[@mutahher2k]

very nice way to define, i never got bored during all time. At start of video, i was annoyed of moving camera. but very soon I started to enjoy moving camera. (my heart synced​ with camera movements)

[@anandmirji831]

I wish PLLs were taught like this in school.

[@KangJangkrik]

I wish highschool teaches practical knowledge, so trainer like me don't have to train new employee "from scratch" (also yes, they're still not properly get it at college)

[@GabeShaikh]

Phenomenal! Best explanation of PLL I've ever seen!

[@dardosordi]

Best analog channel ever!

[@TheKolcantas]

Excellent video, thank you very much! Someone finally gave an insight about how a PLL can be used for frequency multiplying or dividing!

[@jimzweighaft8079]

Analog Simpson Multimeter! Haven't seen those since graduate school. They're still cool.

[@abdullahsy7072]

Thanks so much for this video. You just clear out a big misunderstanding I had for many years. wish you all the happiness :D

[@prajanpradhan6089]

Wow...That is what I call an explanation.....Thank You very much.

[@bhavani1089shankar]

you are amazing w2aew, i wanted to do this experiment and i will get back to you and share my experiences after that

[@優さん-n7m]

+Bhavani Shankar and...?

[@ozandogan948]

Best explanation I have ever watched.

[@kellyklaask7su990]

I really like your videos! LOTS of good information. Thank you!

[@henrihoopkins2822]

Excellent video as compared to other videos I have looked at on the same subject. There is nothing like comparing paper design to building the circuit and seeing how close the two agree.

[@DrCassette]

Thanks for this great explanation!

[@acestudioscouk-Ace-G0ACE]

This is a very informative video and easy to understand for non techies like me. Thanks.

[@alvaro6917]

Perfect explanation for the pll and the frecuency synthesizer

[@histopixelfilms6778]

I really enjoy these video's......even as an old techo, I still find them inspiring

[@agstechnicalsupport]

A very good video explaining the basics of phase locked loop circuits theory along with some experiments.

[@davidlisney2597]

Once again a fascinating video, it is funny how all sorts of applications spring to mind. Many years ago I worked for a company that used a PLL in a squelch circuit... it was an SSB radio and the PLL was in the audio path... unfortunately I don't remember the details but it did work pretty well.

[@902Steeler]

I apreciate the work that you put in to make these video tutorials thank you

[@2z250]

Thank you it’s really useful 😊 I’m doing a project on radio and your video is the most useful I found yet

[@michaelwirtzfeld7847]

I love the Simpson meter in front of the circuit board. Memories of high school electronics class. Thanks, Mr. Banfield - LBHS!

[@RanjanNandi-i7f]

Best video for pll inderstamnding .

[@ahmetserdr2920]

Sir , i always like your videos. When i dont understand what you say i know that is my problem because you are perfect 😊

[@willk9165]

dude you should have 1M subs.

[@yaghiyahbrenner8902]

This is so useful especially useful for demystifying a micro-controller PLL block.

[@VintageLabSilvioPinheiro]

Brillant explanations. U are the master

[@zacharypeattie]

Awesome video! Learning about this in my PMEL course for the Air Force. Should be fun calibrating with this explanation thank you!

[@naranjodiogenes]

Excelent explanation. Congratulations!

[@TheCrazyInventor]

When I saw your breadboard for the first time, I just burst out in laughter! Never seen that many scope probes and hooks on a small breadboard like that before. :D

[@onefractalfield6818]

I got so much understanding GOOD PERSON. THANK YOU. YOU DAMN GENIUS