I have to say that your videos are so informative and useful for a budding electrical engineer. I feel my professors skipped past many of the detailed explanations you've provided and you've really helped fill in the gaps. Cheers!
you are absolutely right. I am sorry to necro this old comment. But thanks to you 2 guys and a few others ( Mr. Carlson's lab, Necroware etc. ) for the past 2 years I have developped myself enough in electronics, to be hired as a tech, passed my Ham license, and I am on the verge of starting my own repair company ( july 2022 .... in theory ) Huge thanks, we need more people like you guys, you are drivers of changes. much love!!
Dude your the man. My god this is so good. As a recent engineer new to the field the level of education you offer is just superb. 14 minutes of video bringing so many concepts to life. Well done!
Thanks for all the great work you did on this video... Setting up the lab, showing the schematic with a clear and slow narration of each in conjunction with the other which produces a crystal clear, Sin and Cos free explanation of how an RF mixer works. Thanks!
Phenomenal video, thank you. I watched no less than 20 videos on super heterodyning until I arrived at yours and then the concept became clear as to what the role of my 6A7 pentagrid converter is. Thank you for Sharing your expertise.
Oh my God I love your videos. Your block diagrams give such great insight as to the flow of signal and how it is changed. Then your equipment shows how we can look at those signals being changed. Finally, you provided a great explanation as to how a band pass filter can help the mixer not have to create an IF from two incoming RF signals. Excellent!
GREAT VIDEO. I'm a COM/NAV Avionics troop for the Air Force. Also an Electrical Engineer major. Just found your channel and I feel like I just struck gold. PLEASE keep pumping these videos out. Don't be afraid to get more and more advanced either. Although I knew a good bit of this stuff, I still learned a lot. THANK YOU!!
Very valuable presentation! I could not get much of the details but the set-up alone teaches a lot, probably worth 500 pages of a book you would never get in the first place. Thank you Alan!
Great video. Showing the mixer output helps greatly in understanding the function of not just the mixer, but the functions of the filters. I've seen a number of these type of videos describing receiver systems, but nobody has shown the concepts so clearly and concisely. Thanks!!
Great video.I am a physician MD from India.Amidst Covid-19 very interesting.Clearly shown Lo , RFin, IF out, various spurious waves and way of tuning by mixer. Clear use of 10.7 ceramic filter.Again Thanks
Thank you for showing the waves on the oscillator that show the various possible frequency images. I was having trouble visualizing what was really going on from the words in theory.
This clears up so much for me. Thank you. The one thing I don't quite understand is how to choose an amplitude or RMS value for the LO. I understand that if we want an IF freq of 455kHz, then the difference between F(LO) and F(RF) should be 455kHz. But how do we decide what the peak-to-peak voltage of the LO signal should be?
That depends entirely on the design of the mixer. The specs for the mixer will state the LO drive power. Often times, mixers are called Level-n, such as Level-7 or Level-13, indicating that they want a 7dBm or 13dBm drive level.
I've been watching and reading enough radio theory that I watched this introduction to mixers and didn't actually learn anything. I appear to have graduated from the "Basics of" videos. :) It's time to watch some of your more advanced videos. I'm learning. Thank you.
Another excellent video, you have obviously taken time to build some excellent test rigs. You mention that you may do a video on PLLs, I am sure that would be excellent too, though probably easier to demonstrate on an old CB radio or similar rather than build a test rig from scratch. Many years ago I was mystified by the operation of a Huff and Puff stabiliser, it was a circuit for a homebrew amateur project. Years later I was working on an HS400 frequency generator and suddenly the penny dropped as to how a Huff and Puff stabiliser worked. A poor mans PLL! I have been an rf engineer and hobbyist for a very long time, but watching your videos is still a great way to get another take on things. To the beginners in the subject I would encourage you to watch the videos closely, this is good information presented really well.
Truly excellent, I have more of a grasp of IF functionality after this video than after reading umpteen text based explanations. Brilliant, and many thanks for turning on the light at full brightness :)
Congratulations for your clear, very very clear explanation and excelent demonstration. I loved to know the Tektronics MDO4104 time and frequency domain. Back in the 70's i used to work with spectrum analyzer. I am an electronics engineer in Brazil.
Thank You so much, Alan. I have repaired many vintage amps but always come to a dead stop on the tuner sections. I just picked up the required UHF test equipment and I'M GOING IN. Mini spectrum analyzer with NF probe and UHF SG. Have a Marantz 2220b with no stereo lock. Might just be in the MPX demodulator or IF amp but I want to see it all! What a great video!
Thanks so much for the time and effort and thought that you put into your videos. Topics that I thought I understood are made so much clearer. Your schematics, and outlines are so concise yet easy to understand. You have a "gift" for teaching. Thanks for sharing it.
Excellent video and use of real signals and filtering to explain the topic. I wish I had seen this type of explanation in my EE education long long ago!
Thanks. I've been aware of RF mixers, but never understood the basics. Tweaking the LO while watching the IF spectrum really made it clear how they relate. I'd love to see example filtered IF waveforms against AMed input ~ and limits of AM freq vs carrier.
A couple questions here... 1. When I tune to a station, let's say 92.3, does that mean the radio station transmits at a different frequency? 2. Are some of the intermods higher in power than the fundamentals? I was surprised to see that. Your content is the best on youtube btw!!! Hands down.
Radio stations are strictly regulated, it is highly unlikely that their signal would include harmonics. Intermod products at the output of the mixer can be higher that the fundamental.
great video, thank you very much Sir. I almost went down the way of ganged tuning of the LO, RF amp and mixer. I am actually working on such project for my final year design.
Hello! This is VU2RJV here with a huge thanks and genuine appreciation of this seminal video! Your clarity and ability to explain in a lucid way is just fantastic. May i request you to also tell us the various possible cases that can occur in designing the filter eg, you've explained two cases where RF-LO or LO-RF can occur depending on which frequency is greater. You've mentioned that the side band Inversion will occur. Can you explain the math? Also, could you please cover other cases as we go from a lower to higher RF and go across bands ? Thanks
The mixer gives you the sum and difference frequencies between the input and the LO, as well as the harmonics components: So, the output will have: F(IN)+F(LO) F(IN)-F(LO) or F(LO)-F(IN), depending on which is greater and the harmonic combinations: nF(IN)+/-m(F(LO) or nF(LO)+/-mF(IN)
thank you - great video, clear concise, and a great demonstration that was easy to follow but also included a tremendous amount of incite into the function of a mixer and the resultant IF signal. This answered my question about Heterodyning.
Great video as always, i learn a lot from these. A lot of this i get at university but theres no teacher like you, very nice practical examples. Thank you!
Great video for me learning this stuff. I looked up that ceramic filter, so I take it with their wider bandwidth relative to a crystal you wouldn't use them as an IF filter for narrow band applications like SSB? Or are there other stages downstream where using the ceramic filter would be appropriate. Thanks for the knowledge
IMO, this video is more appropriate to the discussion of using the NE602 to modulate an audio signal to produce an AM signal that could be used to transmit. (Maybe I'm wrong...? And it is an excellent video!!) It would be cool, though, to see instead how the 602 would transform an input AM carrier plus audio for receive. How does the mixing function take an AM modulated signal, in the time domain and pull out the audio component? (Or does it?) (I ask all of this as an EE who studied this in college in the 70s and either have forgotten or never completely knew. The college presentation is to show the time domain explanation but what I would like to know is how does the mixer translate the received signal in the time domain. As I think about it it is not obvious to me how it would do it...?
Thanks for the helpful video. I'd really appreciate it if you can explain how the amplitude powers are calculated theoretically. For example, at 17.70 MHz the spectrum analyzer reads -50.9 dBm. I want to know how that value is found. Cheers
Yet another very good video. I found it both interesting and greatly informative. Unfortunately we did not get as far as modulation operation, in a practical sense, in the electronic course I did. Thanks for this more practical video.
Great video thank you. Q: how does the mixer "filter out" all the other frequencies of the band presented at it's input by varying the local oscillator?
In short - it doesn't. All frequencies within the rated input bandwidth of the mixer are mixed with the LO, and all of those mixing products appear at the output. It is up to the user to filter unwanted signals from the input (so they're not converted), and from the output (to select which mixing products you want to keep).
Ive been a ham for 25 Years, read the Hand book chapters over & over, but actually SEEING it, makes it ALL come together. Infact, you have sparked an interest for me to start getting creative, as I have always dreamed of building a receiver, that not only was functional, but of high quality & preformance specs. I havent gone threw all of your material, so I will ask, do you have videos on mode specific detection? IE AM detection, FM , SSB.. ect? Also, 1 last question, I'm starting to think about proper gear I would like to get to actually make a HB receiver , and I know I will need a LCR meter to make BFS's, many of the hand held options in the 100-200 dollar range only have the ability to test at 1 or mabey 2 given frequencies. Would I be correct in my assumption that in order to properly make BPF;s of decent quality, I would need to be able to test inductors @ their intended frequency of operation? Thanks for the vids!
I don't have videos up on specific demodulation types yet. However, I have several "receiver walk-through" videos that discuss the demodulators as part of the schematic review process. Personally, I haven't found it necessary to test these components at the frequency they're going to be used at. You just have to be aware of the self-resonant frequency of them, and operate below that. I have several vids that discuss the basics of inductors and capacitors, how to measure them, etc.
As usual a brilliant video Alan. Love how you connect the dots between theory and practical. Questions 1) The IF filter did not affect the noise floor at all in the spectrum. Is that because the stop band of the IF filter is wider than the span you used? 2) Can you please shed a little light on what happens lets say if the matching transformers don't result in perfect match or what happens when there is LO leakage. 3) LOs are also responsible for introducing phase noise because of the PLL. But this is hard to visualize. And your videos have helped me visualize. Could you make a video for this. Thanks in advance.
1) The filter didn't affect the noise floor because the it's the noise floor of the spectrum analyzer itself. 2) See my videos on reflections and terminations to understand what happens when you don't have a perfect match. In this application, the main effect is that you won't get maximum power transfer into or out of the mixer (conversion loss will be higher). 3) I'll add it to my list.
w2aew Thanks for the prompt response. I got to your faq video finally so will be able to navigate better through the videos. Will check out the mixer video.
w2aew Awesome Video covering the basics. Can you make a video on various parameters/performance metrics of a mixer such as drive level, 3d order intercept point etc
What type of ferrite or composite cores are those transformers and what would be a good rule of thumb way to select an appropriate core for ref transformer without getting into really complex math. Thanks KE8SPI
I am an electronic graduate who's just getting started on this RF related modulation and demodulation ccts. Although I have gone through many videos of yours, this seems the best one to start. 1. Do you think for now, you can tell us a easy out of the box mixer cct to buy to repeat this experiment in laboratory? I would love to make this but I think I should first do this experiment in lab. 2. Can you tell us a good book to start reading so we can truly start to make sense of advance words to say. This is too important. A single book that can give me the good basics in this field . Thank you heaps and a big 🗻 mountain
A decent little connectorized mixer to start with would be something like this: www.minicircuits.com/WebStore/dashboard.html?model=ZX05-1L-S%2B A good book to start with would be "RF Circuit Design" by Bowick. Another good reference would be the "ARRL Handbook for Radio Communications". For more circuit level applications, look at "Experimental Methods for the Radio Amateur".
w2aew wow thanks so much for your quick response. I just started my higher studies now. And I want to do my research in line with SDR and RF (the cool stuff you do that don't let me sleep) . I am still a very beginner in your planet but expert in embedded systems world. I will refer the books from the library if not find by other means. I will need to definitely buy several of such mixers. I want to test IQ modulation using them afterwards. I.e. Next I want to implement a direct conversion receiver. You speak about it on ua-cam.com/video/RHFZUqUM8DY/v-deo.html under "#262: IQ Modulator Basics: Operation, measurements, impairments" And for that I need two mixers as I saw from your video here(may be i'm wrong) . Perhaps if I have two of the ZX05-1L+ I will be able to implement a simple direct conversion receiver. I don't want to do anything fancy. I do not need the ZFMIQ-70ML IQ modulators for this experiment right? Just want to show my professor a demo of fundamentals. I will recommend your channel to my whole group. Lots of thanks from Singapore
I’m just curious how you came up with the input and output transformers for use with the NE602AN. Were these salvaged from another circuit or made from scratch? I would like to duplicate your experiments/demonstrations, and would need to fabricate the transformers. I realize RF transformer design is way beyond the scope of the experiment, is there something simple I can fabricate, or too complex?
how are spurs in LO generated? I have seen on my board that its usually at LO + n*fclk or LO - n*fclk....where 'fclk' is the various clocks generated by frequency synthesizer block.....can somebody explain a little bit or point me to some text?
What about using the PI5V331 configured as a Double Balanced QSD fed via a BALUN which outputs two pairs of signals via 0u1 ceramic capacitors which get combined using 2x Motorola MC1350 which drive a RF phase combiner to get rid of sproggies and is driven via a Johnson Counter run from an oscillator operating at 4x the wanted frequency I.E. ((fin+10.240)*4) the output will hopefully be at 10.240mhz and no sproggies.
I have to say that your videos are so informative and useful for a budding electrical engineer. I feel my professors skipped past many of the detailed explanations you've provided and you've really helped fill in the gaps. Cheers!
Thank you!
Everything you do is awesome.
you are absolutely right. I am sorry to necro this old comment. But thanks to you 2 guys and a few others ( Mr. Carlson's lab, Necroware etc. ) for the past 2 years I have developped myself enough in electronics, to be hired as a tech, passed my Ham license, and I am on the verge of starting my own repair company ( july 2022 .... in theory ) Huge thanks, we need more people like you guys, you are drivers of changes. much love!!
Dude your the man. My god this is so good. As a recent engineer new to the field the level of education you offer is just superb. 14 minutes of video bringing so many concepts to life. Well done!
This is a great demo. Seeing the time and frequency domain together, and with the unfiltered and filtered mix response is perfect.
Thanks for all the great work you did on this video... Setting up the lab, showing the schematic with a clear and slow narration of each in conjunction with the other which produces a crystal clear, Sin and Cos free explanation of how an RF mixer works. Thanks!
Phenomenal video, thank you. I watched no less than 20 videos on super heterodyning until I arrived at yours and then the concept became clear as to what the role of my 6A7 pentagrid converter is. Thank you for Sharing your expertise.
Oh my God I love your videos. Your block diagrams give such great insight as to the flow of signal and how it is changed. Then your equipment shows how we can look at those signals being changed. Finally, you provided a great explanation as to how a band pass filter can help the mixer not have to create an IF from two incoming RF signals. Excellent!
A masterpiece of demonstration and explanation. Your notes are the best.
I recently got into electronics and your videos help more then ever. I love the way you create your videos.
GREAT VIDEO. I'm a COM/NAV Avionics troop for the Air Force. Also an Electrical Engineer major. Just found your channel and I feel like I just struck gold. PLEASE keep pumping these videos out. Don't be afraid to get more and more advanced either. Although I knew a good bit of this stuff, I still learned a lot. THANK YOU!!
You covered 100 pages in Art of Electronics in 10 minutes, and I got it, tnx
So that's how that works. Thank you for the clear explanation with visual examples.
Been reading a RF Microelectronics book only to fall half asleep. Thank you for the video. It's very illustrative and intriguing.
Very valuable presentation! I could not get much of the details but the set-up alone teaches a lot, probably worth 500 pages of a book you would never get in the first place. Thank you Alan!
you are at the top of Explaining RF Electronic and Radio Communication in Easy way
Great video. Showing the mixer output helps greatly in understanding the function of not just the mixer, but the functions of the filters. I've seen a number of these type of videos describing receiver systems, but nobody has shown the concepts so clearly and concisely. Thanks!!
Great video.I am a physician MD from India.Amidst Covid-19 very interesting.Clearly shown Lo , RFin, IF out, various spurious waves and way of tuning by mixer. Clear use of 10.7 ceramic filter.Again Thanks
Thank you for showing the waves on the oscillator that show the various possible frequency images. I was having trouble visualizing what was really going on from the words in theory.
This clears up so much for me. Thank you. The one thing I don't quite understand is how to choose an amplitude or RMS value for the LO. I understand that if we want an IF freq of 455kHz, then the difference between F(LO) and F(RF) should be 455kHz. But how do we decide what the peak-to-peak voltage of the LO signal should be?
That depends entirely on the design of the mixer. The specs for the mixer will state the LO drive power. Often times, mixers are called Level-n, such as Level-7 or Level-13, indicating that they want a 7dBm or 13dBm drive level.
@@w2aew Interesting. Can't seem to find anything on the NXP SA606 datasheet. I'll keep looking around.
I've been watching and reading enough radio theory that I watched this introduction to mixers and didn't actually learn anything. I appear to have graduated from the "Basics of" videos. :) It's time to watch some of your more advanced videos. I'm learning. Thank you.
Read all intructions again and again.....as lesson....thanks for posting Alan...Dinos
Alan, this was absolutely an awesome video - great setup for the explanation. KM5L
Another excellent video, you have obviously taken time to build some excellent test rigs. You mention that you may do a video on PLLs, I am sure that would be excellent too, though probably easier to demonstrate on an old CB radio or similar rather than build a test rig from scratch.
Many years ago I was mystified by the operation of a Huff and Puff stabiliser, it was a circuit for a homebrew amateur project. Years later I was working on an HS400 frequency generator and suddenly the penny dropped as to how a Huff and Puff stabiliser worked. A poor mans PLL!
I have been an rf engineer and hobbyist for a very long time, but watching your videos is still a great way to get another take on things.
To the beginners in the subject I would encourage you to watch the videos closely, this is good information presented really well.
I did make a video on the basics of PLLs. Here's the link:
Basics of Phase Locked Loop Circuits and Frequency Synthesis
Wahhhh sir this was better than all my school rf lesson's!
Excellent video, simple yet incredibly clarifying. Thank you so much!
Alan, thank you. You really have a beautiful way to explain electronics
Truly excellent, I have more of a grasp of IF functionality after this video than after reading umpteen text based explanations. Brilliant, and many thanks for turning on the light at full brightness :)
Congratulations for your clear, very very clear explanation and excelent demonstration. I loved to know the Tektronics MDO4104 time and frequency domain. Back in the 70's i used to work with spectrum analyzer. I am an electronics engineer in Brazil.
Another very good tutorial Alan, 73 Bob Johansen. It was good talking with you at the NJARC swapmeet
Hi Bob - yes, good to see you too at NJARC. Thanks for watching!
Thank You so much, Alan. I have repaired many vintage amps but always come to a dead stop on the tuner sections. I just picked up the required UHF test equipment and I'M GOING IN. Mini spectrum analyzer with NF probe and UHF SG. Have a Marantz 2220b with no stereo lock. Might just be in the MPX demodulator or IF amp but I want to see it all! What a great video!
Did you see my recent video on how a superheterodyne receive works?
I am from Brazil.Excellent video showing theory and practice! I loved your ressources, specially the scope with mixed domain! Congrats!
Thanks so much for the time and effort and thought that you put into your videos. Topics that I thought I understood are made so much clearer. Your schematics, and outlines are so concise yet easy to understand. You have a "gift" for teaching. Thanks for sharing it.
Ah Ha! Finally. Been trying to get my head round this for ages. Thank you. Great explanation.
binge watching all the circuit tutorials, trying to remember to like and comment on each as well
Very well done. Easy to understand and follow. Including the test equipment along with the schematics really helped with understanding. Thanks!
New ham here. I found this very educational. Thanks for the vid.
Thanks for your time to make this presentation. It was very helpful.
Extremely good explanation and visualization! Saved it so I can watch it again :D
I was very impressed when you switched the ceramic filter into the mixer's output. The other mixer products just vanished.
This is a really good video! I'm pretty much a beginner, you explained mixers so well I got it first time. Thank-you!
After watching this video, I could understand how mixer works. Thanks.
Excellent video and use of real signals and filtering to explain the topic. I wish I had seen this type of explanation in my EE education long long ago!
Fascinating, I'm taking up SWL and will be revisiting this many times. Well planed out presentation and description, loved it thanks.
Very well demonstrated and explaining image frequencies.
Thanks. I've been aware of RF mixers, but never understood the basics. Tweaking the LO while watching the IF spectrum really made it clear how they relate. I'd love to see example filtered IF waveforms against AMed input ~ and limits of AM freq vs carrier.
Excellent presentation, explanation, and demonstration. It really makes the concepts clear.
very good video. Using the spectrum analyser made it all become clear. Thank you for taking the time to make this video
I like how you make it sound so easy.you're a great teacher.
Excellent explanation about the mixer products with practical lab test results. Great job sir. Thanks.
A couple questions here...
1. When I tune to a station, let's say 92.3, does that mean the radio station transmits at a different frequency?
2. Are some of the intermods higher in power than the fundamentals? I was surprised to see that.
Your content is the best on youtube btw!!! Hands down.
Radio stations are strictly regulated, it is highly unlikely that their signal would include harmonics. Intermod products at the output of the mixer can be higher that the fundamental.
great video, thank you very much Sir. I almost went down the way of ganged tuning of the LO, RF amp and mixer. I am actually working on such project for my final year design.
Hello! This is VU2RJV here with a huge thanks and genuine appreciation of this seminal video! Your clarity and ability to explain in a lucid way is just fantastic.
May i request you to also tell us the various possible cases that can occur in designing the filter eg, you've explained two cases where RF-LO or LO-RF can occur depending on which frequency is greater. You've mentioned that the side band Inversion will occur. Can you explain the math? Also, could you please cover other cases as we go from a lower to higher RF and go across bands ? Thanks
The mixer gives you the sum and difference frequencies between the input and the LO, as well as the harmonics components:
So, the output will have:
F(IN)+F(LO)
F(IN)-F(LO) or F(LO)-F(IN), depending on which is greater
and the harmonic combinations:
nF(IN)+/-m(F(LO) or nF(LO)+/-mF(IN)
Thank you very much for all your video and sharing your knowledge with people! I've learned and still learning a lot from you!!!
thank you - great video, clear concise, and a great demonstration that was easy to follow but also included a tremendous amount of incite into the function of a mixer and the resultant IF signal. This answered my question about Heterodyning.
Excellent video, was exactly what I was looking for. Concise and clear with a demonstration. Can't sk for more!
You certainly have a gift for teaching. Thank you - and if you had a 'donate' button, I'd hit it.
So grateful to you for producing this type of content. Don't really know how we can help you in return.
I'm happy that you see value in my content.
Great video as always, i learn a lot from these. A lot of this i get at university but theres no teacher like you, very nice practical examples. Thank you!
I never comment videos, but this one deserve it. Excellent explanation and setup. Totally Like.
Sir, you put a lot of work into this video. And, it was an outstanding educational presentation. Thank you. 73, Chuck - AA5WG
Thank you for your kind words, Chuck. I am happy that you enjoyed this video.
Amazing job! Informative yet easy to understand videos! Thanks a lot !
Great stuff! I can't get enough of this channel. So good.
Great video for me learning this stuff. I looked up that ceramic filter, so I take it with their wider bandwidth relative to a crystal you wouldn't use them as an IF filter for narrow band applications like SSB? Or are there other stages downstream where using the ceramic filter would be appropriate. Thanks for the knowledge
Great demonstration.
IMO, this video is more appropriate to the discussion of using the NE602 to modulate an audio signal to produce an AM signal that could be used to transmit. (Maybe I'm wrong...? And it is an excellent video!!) It would be cool, though, to see instead how the 602 would transform an input AM carrier plus audio for receive. How does the mixing function take an AM modulated signal, in the time domain and pull out the audio component? (Or does it?) (I ask all of this as an EE who studied this in college in the 70s and either have forgotten or never completely knew. The college presentation is to show the time domain explanation but what I would like to know is how does the mixer translate the received signal in the time domain. As I think about it it is not obvious to me how it would do it...?
Thanks for the helpful video. I'd really appreciate it if you can explain how the amplitude powers are calculated theoretically. For example, at 17.70 MHz the spectrum analyzer reads -50.9 dBm. I want to know how that value is found. Cheers
Yet another very good video. I found it both interesting and greatly informative. Unfortunately we did not get as far as modulation operation, in a practical sense, in the electronic course I did. Thanks for this more practical video.
Brilliant demonstration, thanks a bunch!
Great video, exactly what I was looking for.
Thank you very much for sharing this with us.
Amazing video... Great work... Hope you could do more videos
Exactly the video I was looking for, great content. Thanks!
Great video thank you.
Q: how does the mixer "filter out" all the other frequencies of the band presented at it's input by varying the local oscillator?
In short - it doesn't. All frequencies within the rated input bandwidth of the mixer are mixed with the LO, and all of those mixing products appear at the output. It is up to the user to filter unwanted signals from the input (so they're not converted), and from the output (to select which mixing products you want to keep).
It coud be nice to get some screen shoots of Oscilloscope and some pdf of those notes.
Very clear explanation. Thank you!
Hasan Kaya I'll post a link to pdf notes later today, after I scan and upload them.
Hasan Kaya Notes are up: www.qsl.net/w2aew//youtube/RFmixersheterodyne.pdf
Thank you wery much.
one of the best explanations ever!
Thank you sir for explanation and patient :) now it is a bit clear for me.
Best regards
I LOVE YOU. Thank you MAN. Great. I LOVE YOU.
FANTASTIC video, I'we seen it a lot of times. A question: Is the IF filter designed for a specific impedance?
Yes, typically tuned to the output and input impedance of the circuits preceeding and following stages.
Awesome tutorial thanks! IF was messing with me that made it simple to understand,
Ive been a ham for 25 Years, read the Hand book chapters over & over, but actually SEEING it, makes it ALL come together. Infact, you have sparked an interest for me to start getting creative, as I have always dreamed of building a receiver, that not only was functional, but of high quality & preformance specs. I havent gone threw all of your material, so I will ask, do you have videos on mode specific detection? IE AM detection, FM , SSB.. ect? Also, 1 last question, I'm starting to think about proper gear I would like to get to actually make a HB receiver , and I know I will need a LCR meter to make BFS's, many of the hand held options in the 100-200 dollar range only have the ability to test at 1 or mabey 2 given frequencies. Would I be correct in my assumption that in order to properly make BPF;s of decent quality, I would need to be able to test inductors @ their intended frequency of operation? Thanks for the vids!
I don't have videos up on specific demodulation types yet. However, I have several "receiver walk-through" videos that discuss the demodulators as part of the schematic review process. Personally, I haven't found it necessary to test these components at the frequency they're going to be used at. You just have to be aware of the self-resonant frequency of them, and operate below that. I have several vids that discuss the basics of inductors and capacitors, how to measure them, etc.
Excellent, thank you so much for your reply & hard work for putting these fantastic , educational & informational vids up
imscuba c
Thanks for the video's you have done I just passed my advanced exam and these really help.
Excellent, congratulations, and glad I could help!
Very nicely done, thank you...it's been a great help
Man you rock. Wonderful tutorial video.
Thank you for this easy to understand topic.
Good practical demonstration. Thank you.
As usual a brilliant video Alan. Love how you connect the dots between theory and practical.
Questions
1) The IF filter did not affect the noise floor at all in the spectrum. Is that because the stop band of the IF filter is wider than the span you used?
2) Can you please shed a little light on what happens lets say if the matching transformers don't result in perfect match or what happens when there is LO leakage.
3) LOs are also responsible for introducing phase noise because of the PLL. But this is hard to visualize. And your videos have helped me visualize. Could you make a video for this.
Thanks in advance.
1) The filter didn't affect the noise floor because the it's the noise floor of the spectrum analyzer itself.
2) See my videos on reflections and terminations to understand what happens when you don't have a perfect match. In this application, the main effect is that you won't get maximum power transfer into or out of the mixer (conversion loss will be higher).
3) I'll add it to my list.
w2aew Thanks for the prompt response. I got to your faq video finally so will be able to navigate better through the videos. Will check out the mixer video.
Nice video. How would you measure the Noise Figure of the Mixer?
w2aew Awesome Video covering the basics. Can you make a video on various parameters/performance metrics of a mixer such as drive level, 3d order intercept point etc
This is such a great tutorial. Thank you for sharing!
What type of ferrite or composite cores are those transformers and what would be a good rule of thumb way to select an appropriate core for ref transformer without getting into really complex math. Thanks KE8SPI
Intelligent people who understand that.!
Beautifully demonstrated
Thank You Very Much - this was tremendously educational!
So basically it's shifting the whole frequency band behind a window by the amount selected with the LO?
Yes.
*****
Nice! I finally understood the principle. Thank you for sharing and explaining.
Your videos are excellent. Thank you so much for sharing your knowledge in a clear and concise way.
I am an electronic graduate who's just getting started on this RF related modulation and demodulation ccts. Although I have gone through many videos of yours, this seems the best one to start. 1. Do you think for now, you can tell us a easy out of the box mixer cct to buy to repeat this experiment in laboratory? I would love to make this but I think I should first do this experiment in lab.
2. Can you tell us a good book to start reading so we can truly start to make sense of advance words to say. This is too important. A single book that can give me the good basics in this field . Thank you heaps and a big 🗻 mountain
A decent little connectorized mixer to start with would be something like this:
www.minicircuits.com/WebStore/dashboard.html?model=ZX05-1L-S%2B
A good book to start with would be "RF Circuit Design" by Bowick. Another good reference would be the "ARRL Handbook for Radio Communications". For more circuit level applications, look at "Experimental Methods for the Radio Amateur".
w2aew wow thanks so much for your quick response. I just started my higher studies now. And I want to do my research in line with SDR and RF (the cool stuff you do that don't let me sleep) . I am still a very beginner in your planet but expert in embedded systems world. I will refer the books from the library if not find by other means.
I will need to definitely buy several of such mixers. I want to test IQ modulation using them afterwards.
I.e. Next I want to implement a direct conversion receiver. You speak about it on ua-cam.com/video/RHFZUqUM8DY/v-deo.html under "#262: IQ Modulator Basics: Operation, measurements, impairments"
And for that I need two mixers as I saw from your video here(may be i'm wrong) . Perhaps if I have two of the ZX05-1L+ I will be able to implement a simple direct conversion receiver.
I don't want to do anything fancy. I do not need the ZFMIQ-70ML IQ modulators for this experiment right?
Just want to show my professor a demo of fundamentals. I will recommend your channel to my whole group. Lots of thanks from Singapore
I’m just curious how you came up with the input and output transformers for use with the NE602AN. Were these salvaged from another circuit or made from scratch?
I would like to duplicate your experiments/demonstrations, and would need to fabricate the transformers. I realize RF transformer design is way beyond the scope of the experiment, is there something simple I can fabricate, or too complex?
how are spurs in LO generated? I have seen on my board that its usually at LO + n*fclk or LO - n*fclk....where 'fclk' is the various clocks generated by frequency synthesizer block.....can somebody explain a little bit or point me to some text?
What about using the PI5V331 configured as a Double Balanced QSD fed via a BALUN which outputs two pairs of signals via 0u1 ceramic capacitors which get combined using 2x Motorola MC1350 which drive a RF phase combiner to get rid of sproggies and is driven via a Johnson Counter run from an oscillator operating at 4x the wanted frequency I.E. ((fin+10.240)*4) the output will hopefully be at 10.240mhz and no sproggies.
explain much better than my lecture.....
You are amazing! Thanks for this video!