Bob says, "Let me know what you think". So this is what I think, have a beverage on me. Thank you for making this. If you wonder: "is this too much detail?" No! "Could I add more detail?", you could, but I think this one was right on. "Does anyone really want to see this?", I do. Please keep this up as I am sure there are many of us who enjoy learning this or at least a refresher for the rest. Am really looking forward to this series and thanks again. Great stuff.
Thank you very much. A couple weeks I had started to go off the deep end so to speak with lengthy discussions. Glad I decided to take a break and rethink my approach. It's so easy to get bogged down in the details.
@@bandersentv Thanking you. I do totally get that. In a past life,,, I have been asked to lecture at a couple of universities and NASA about my particular engineering field because I would do the same thing anyone who is good at teaching board games knows: focus on the fundamentals and basic processes first and resist getting into too much nuance and exceptions, because you can, until later so that you don't lose the grasp of people watching. Also some background info adds helpful interest, such as your aside about color TV being reverse compatible and some of the implications, providing some understanding why things developed as they did, not necessarily as one would think they "should have". People would tell me, at last, I get it. There are already people here telling you essentially the same thing in these comments. That means you succeeded. Thanks again.
Wow…this is the first time I’ve had this explained to me in simple terms and graphics in a way I understand. Frankly, as a tinkerer and a “slap it and recap it” tv and radio guy I’ve been somewhat embarrassed to ask questions like this on VK. I don’t know where you find the time to be a presence on the discussion boards, make RUclips videos, repair TVs and work a 9 to 5 job but those of us in this hobby who love these old pieces of history appreciate your mentoring and teaching so much. This was no doubt the foundation baseline I need to start fine tuning my pieces. I can get them to work…now I want to get them to work well!
Easy - stop sleeping LOL. No seriously it's because I'm fortunate to work from home 4 days a week. Those extra 2-3 hours a day make all the difference.
Excellent! Takes be back forty years to my electronic service engineering classes. I can hear Dr. Fetters and Dr. Goodwin explaining these circuits such in a similar manner as you did here. They focused mostly on solid state but made sure we knew vacuum tube technology as well. These tuned circuits are applicable to both. Please keep up the series! Now you need to introduce the formulas, add hands on labs, give some tests, and award an AAS or BS in the new field of Vintage EET/EST. One caveat, you put a hold on awarding a degree until a student pays their un-paid parking tickets. (I think I owned nearly as much in parking tickets as I did tuition.)
Seeing this, this morning, (6/27), it reminded me that even analog TV has a separate audio that is transmitted with the video, and kept in sync. Same thing with digital video, the video and audio have separate codecs and are kept in sync. I did TV broadcast technician classes in the late 1980's at a 2 year voc tech and in electronic theory portion, this is some of what we learned, in part to pass the SBE test (society of broadcast engineers). This was when everything was still tape based and analogue, including editing. Essentially, when you are watching a B&W TV, it simply ignores the color burst signal and acts like it was never there.
Hi Bob, I've studied this graphic when start my lessons of circuits of televisions BW and colours (NTSC and PAL, our system) here in Brazil on the early 80s. Thanks for the video.
In fact, not only will it spread out, you’ll get a peak at the carrier frequency +/- the lower (signal) frequency. So, if your signal is a 1 kHz tone, you’ll get a spike in the frequency domain 1 kHz away from the carrier on both sides, which one could see on a spectrum analyzer. 😊
I have never worked on a tv. Well, only in the old days to scrap tubes and parts from them on the curb. This was a fun class to watch and I am learning lots from you. You make it easy to listen and follow what your saying. Thanks so much.
Great video and I would like you to continue this topic and even go a step further - I would love to see a series explaining how a vacuum tube TV works - what how it works, which tube is used for what...
Very good explanation in a few minutes. A want to see another video about the frequency and bandwidth conversion in the tuner for the 2 VHF bands. This video bring me a lot of good memories from the mid 70's when I was doing a part time at a TV service center in Jersey. Most of the service was for B&W sets from the late 50 's and early 60's and, just a few color sets. I close my eyes and can remember the head of the service department telling to all technicians "NEVER TOUCH ANY IF OR TUNER TRANSFORMER" unless you have a "VERY GOOD" reason. Actually, 99% of the sets didn't have a misalignment issue. Pretty much it was a "tube changing center". Obviously, after 40 years, we have a very different scenario. Now, most of the restoration projects needs a full recalibration of tuned circuits. That is why, in my opinion, a radio and TV restoration bench, needs "good" test equipment's.
Bob very valuable training and great explanations and well done. Really liked this especially on explaining the color video signals. Many super duper extra big thanks Mike
Absolutely great👍 Really beginning to understand some of it, thank you. I’m Retiring at Christmas, I have a room in my house I want to make to a electronic workshop inspired by yours. I think I begin to have a little knowledge about it, from watching your videos that I want to give it a try, with a simple tube radio.
Bob, I think you did a pretty good job with that. There really is a lot to how a TV system works, a huge amount of thought went in to it. Engineering always involves compromises. There were a couple of times while I was watching I said to myself "That's not really true." or "That's not really how it works." but as an outline it was fine. You may get some comments from people wanting to make corrections but then it does get very involved. There is a book with several editions over the years that is available for download online called "Television Simplified" by Kiver that goes into more detail. "For the serious student" was sometimes said.
Yep, I'm already started to get corrected. Lol. I just wanted to give a very simple idea of what's going on. You don't need to know all that to actually do an alignment. Yes, Kiver is very good. I have a big stack of TV theory books from the 30s-50s
All the years I worked on Color TVs, the fact they used Phase Modulation for the color signal, makes sense. I never realized they actually used 3 types of modulation in the Transmitted TV signal. Now I see why the red & blue color signals from a color bar generator rotate on an X,Y scope, when turning the Hue cont., its a phase relationship. BTW: the TV's audio FM deviation is + & - 75 khz or 150 khz total. PM also was/is used for AM stereo, PM = L - R & amplitude = L + R, but there is more to it then that with controlling distortion.
Peak luminescence power is set via the sync tips. Thus white is near the baseline. Sync buzz in the audio is caused by excessive sync level. High white luminescence pushes up the sync tips resulting in the carrier to become cutoff.
Bob that. Confuses me some. But I get it look forward for more on the subject id listened to my dad. Your doing a great job. I'm getting. Some test eq. Till next time😎♥️
i have always wondered why the RCA CTC-20 only had 2 IF stages, but then again, it seems they cut corners on that chassis, it WAS a weird one, made only to get rid of the left over round tubes.
Hi Bob, in a staggered IF design if the amp stages are in series, how does the next stage get it's frequency range and why doesn't it filter out the previous frequency range? For eg as you drew the first filter centered at 22MHz and then next at 25.3MHz, the 25.3 would be get filtered by the previous 22 stage and then the 25.3 would chop off the 22 that got through. Almost seems like it would more sense for these to be in parallel rather than series though at that point delay would be an issue. Anyway, cool video and hope to see these principals in practice when you do alignments 👍
@@bandersentv Even so, wouldn't the peaks of each successive stage be slightly attenuated, so instead of a "flat top" band pass you'd actually get one that goes slightly "downhill" ?
Not to steal any of Bob's fire on this, here is another video from a guy who knows his radio and test equipment stuff. He is a field engineer for Tektronix in fact and a Ham. You should never limit your knowledge to one source. ruclips.net/video/-A_DxsxPdeI/видео.html
Thanks Bob, but you asked for comments, so here goes. Your explanation of vestigial sideband is not correct. In particular, where you rub out the bottom of the modulated signal. That would mean that you are transmitting the low frequency components along with a DC component, which is of course impossible. If you look at a vestigial sideband transmission on an oscilloscope, it is symmetrical, as it must be. Showing a vestigial sideband transmission properly can only be done in the frequency domain. The passband of a TV receiver also is not quite as you have drawn it. The bottom part is a slope, such that the response curve is half amplitude at the carrier frequency than the, ideally, flat part of the curve. That is so that, once detected, the energy below the carrier adds to the energy immediately above the carrier, effectively giving a flat response right to the carrier, or down to DC once detected. Also, the response at the audio carrier is much lower; only a few percent of the peak response for the video part. This helps reduce any modulation of the audio signal by the video signal in the video detector. (The proceeding comment is only applicable to intercarrier sound systems.). I hope that helps. Cheers. ☺
Yes, I know. You are of course correct.. That's why I said it wasn't how it really works at that point in the video and I said the disclaimer at the beginning. I'm trying to keep it as simple as possible.
![GEEK TIMË [OFFICIAL AUDIO]](http://i.ytimg.com/vi/ry-6RvkH880/mqdefault.jpg)
DAMN! That is the sound of a big-ass lightbulb turning on above my head. Thanks Bob!
Bob says, "Let me know what you think". So this is what I think, have a beverage on me. Thank you for making this. If you wonder: "is this too much detail?" No! "Could I add more detail?", you could, but I think this one was right on. "Does anyone really want to see this?", I do. Please keep this up as I am sure there are many of us who enjoy learning this or at least a refresher for the rest. Am really looking forward to this series and thanks again. Great stuff.
Thank you very much. A couple weeks I had started to go off the deep end so to speak with lengthy discussions. Glad I decided to take a break and rethink my approach. It's so easy to get bogged down in the details.
@@bandersentv Thanking you. I do totally get that. In a past life,,, I have been asked to lecture at a couple of universities and NASA about my particular engineering field because I would do the same thing anyone who is good at teaching board games knows: focus on the fundamentals and basic processes first and resist getting into too much nuance and exceptions, because you can, until later so that you don't lose the grasp of people watching. Also some background info adds helpful interest, such as your aside about color TV being reverse compatible and some of the implications, providing some understanding why things developed as they did, not necessarily as one would think they "should have". People would tell me, at last, I get it. There are already people here telling you essentially the same thing in these comments. That means you succeeded. Thanks again.
Wow…this is the first time I’ve had this explained to me in simple terms and graphics in a way I understand. Frankly, as a tinkerer and a “slap it and recap it” tv and radio guy I’ve been somewhat embarrassed to ask questions like this on VK. I don’t know where you find the time to be a presence on the discussion boards, make RUclips videos, repair TVs and work a 9 to 5 job but those of us in this hobby who love these old pieces of history appreciate your mentoring and teaching so much. This was no doubt the foundation baseline I need to start fine tuning my pieces. I can get them to work…now I want to get them to work well!
Easy - stop sleeping LOL. No seriously it's because I'm fortunate to work from home 4 days a week. Those extra 2-3 hours a day make all the difference.
Excellent! Takes be back forty years to my electronic service engineering classes. I can hear Dr. Fetters and Dr. Goodwin explaining these circuits such in a similar manner as you did here. They focused mostly on solid state but made sure we knew vacuum tube technology as well. These tuned circuits are applicable to both. Please keep up the series!
Now you need to introduce the formulas, add hands on labs, give some tests, and award an AAS or BS in the new field of Vintage EET/EST. One caveat, you put a hold on awarding a degree until a student pays their un-paid parking tickets. (I think I owned nearly as much in parking tickets as I did tuition.)
Seeing this, this morning, (6/27), it reminded me that even analog TV has a separate audio that is transmitted with the video, and kept in sync. Same thing with digital video, the video and audio have separate codecs and are kept in sync.
I did TV broadcast technician classes in the late 1980's at a 2 year voc tech and in electronic theory portion, this is some of what we learned, in part to pass the SBE test (society of broadcast engineers). This was when everything was still tape based and analogue, including editing. Essentially, when you are watching a B&W TV, it simply ignores the color burst signal and acts like it was never there.
Hi Bob, I've studied this graphic when start my lessons of circuits of televisions BW and colours (NTSC and PAL, our system) here in Brazil on the early 80s. Thanks for the video.
Thanks Bob, this does clear things up 🙂
I’m getting a better education on RUclips then my time spent in high school
This series is proving to be incredibly invaluable! Why has nobody done this sooner?! I love it! Can't wait for the rest.
In fact, not only will it spread out, you’ll get a peak at the carrier frequency +/- the lower (signal) frequency. So, if your signal is a 1 kHz tone, you’ll get a spike in the frequency domain 1 kHz away from the carrier on both sides, which one could see on a spectrum analyzer. 😊
I have never worked on a tv. Well, only in the old days to scrap tubes and parts from them on the curb. This was a fun class to watch and I am learning lots from you. You make it easy to listen and follow what your saying. Thanks so much.
Great video and I would like you to continue this topic and even go a step further - I would love to see a series explaining how a vacuum tube TV works - what how it works, which tube is used for what...
Sure, I can do that..I'll make a note
Thank you Bob for the lesson much appreciated! 🎉
Very good explanation in a few minutes. A want to see another video about the frequency and bandwidth conversion in the tuner for the 2 VHF bands. This video bring me a lot of good memories from the mid 70's when I was doing a part time at a TV service center in Jersey. Most of the service was for B&W sets from the late 50 's and early 60's and, just a few color sets. I close my eyes and can remember the head of the service department telling to all technicians "NEVER TOUCH ANY IF OR TUNER TRANSFORMER" unless you have a "VERY GOOD" reason. Actually, 99% of the sets didn't have a misalignment issue. Pretty much it was a "tube changing center". Obviously, after 40 years, we have a very different scenario. Now, most of the restoration projects needs a full recalibration of tuned circuits. That is why, in my opinion, a radio and TV restoration bench, needs "good" test equipment's.
Bob very valuable training and great explanations and well done. Really liked this especially on explaining the color video signals. Many super duper extra big thanks Mike
Fantastic Explanation! Thank you very much Bob!
Absolutely great👍
Really beginning to understand some of it, thank you.
I’m Retiring at Christmas, I have a room in my house I want to make to a electronic workshop inspired by yours.
I think I begin to have a little knowledge about it, from watching your videos that I want to give it a try, with a simple tube radio.
Excellent lesson Bob!
Bob, I think you did a pretty good job with that. There really is a lot to how a TV system works, a huge amount of thought went in to it. Engineering always involves compromises. There were a couple of times while I was watching I said to myself "That's not really true." or "That's not really how it works." but as an outline it was fine. You may get some comments from people wanting to make corrections but then it does get very involved. There is a book with several editions over the years that is available for download online called "Television Simplified" by Kiver that goes into more detail. "For the serious student" was sometimes said.
Yep, I'm already started to get corrected. Lol. I just wanted to give a very simple idea of what's going on. You don't need to know all that to actually do an alignment. Yes, Kiver is very good. I have a big stack of TV theory books from the 30s-50s
This is quality content. Please keep making more!
Bob, that was an awesome explanation. Thank you and I look forward to the rest of the alignment series.
All the years I worked on Color TVs, the fact they used Phase Modulation for the color signal, makes sense. I never realized they actually used 3 types of modulation in the Transmitted TV signal. Now I see why the red & blue color signals from a color bar generator rotate on an X,Y scope, when turning the Hue cont., its a phase relationship. BTW: the TV's audio FM deviation is + & - 75 khz or 150 khz total. PM also was/is used for AM stereo, PM = L - R & amplitude = L + R, but there is more to it then that with controlling distortion.
Great job. Great explanation. Thank You Sir
Peak luminescence power is set via the sync tips. Thus white is near the baseline. Sync buzz in the audio is caused by excessive sync level. High white luminescence pushes up the sync tips resulting in the carrier to become cutoff.
Bob that. Confuses me some. But I get it look forward for more on the subject id listened to my dad. Your doing a great job. I'm getting. Some test eq. Till next time😎♥️
Nicely done bob.
Bob you're absolutely amazing! How do you have the time to do all this stuff! 🤯
Good to the point video Bob.
Very cool and geeky.
i have always wondered why the RCA CTC-20 only had 2 IF stages, but then again, it seems they cut corners on that chassis, it WAS a weird one, made only to get rid of the left over round tubes.
Hi Bob, in a staggered IF design if the amp stages are in series, how does the next stage get it's frequency range and why doesn't it filter out the previous frequency range? For eg as you drew the first filter centered at 22MHz and then next at 25.3MHz, the 25.3 would be get filtered by the previous 22 stage and then the 25.3 would chop off the 22 that got through. Almost seems like it would more sense for these to be in parallel rather than series though at that point delay would be an issue. Anyway, cool video and hope to see these principals in practice when you do alignments 👍
Because those filters are not ideal.
You got it
The filters are not ideal and overlap so enough leaks through each stage that in the end you get the desired response.
@@bandersentv Even so, wouldn't the peaks of each successive stage be slightly attenuated, so instead of a "flat top" band pass you'd actually get one that goes slightly "downhill" ?
@@WardCo Not if you design and align it carefully. The order of frequency peaks matters.
awesome
Not to steal any of Bob's fire on this, here is another video from a guy who knows his radio and test equipment stuff. He is a field engineer for Tektronix in fact and a Ham. You should never limit your knowledge to one source. ruclips.net/video/-A_DxsxPdeI/видео.html
I've been watching his excellent channel for years. Highly recommend
Thanks Bob, but you asked for comments, so here goes. Your explanation of vestigial sideband is not correct. In particular, where you rub out the bottom of the modulated signal. That would mean that you are transmitting the low frequency components along with a DC component, which is of course impossible. If you look at a vestigial sideband transmission on an oscilloscope, it is symmetrical, as it must be. Showing a vestigial sideband transmission properly can only be done in the frequency domain. The passband of a TV receiver also is not quite as you have drawn it. The bottom part is a slope, such that the response curve is half amplitude at the carrier frequency than the, ideally, flat part of the curve. That is so that, once detected, the energy below the carrier adds to the energy immediately above the carrier, effectively giving a flat response right to the carrier, or down to DC once detected. Also, the response at the audio carrier is much lower; only a few percent of the peak response for the video part. This helps reduce any modulation of the audio signal by the video signal in the video detector. (The proceeding comment is only applicable to intercarrier sound systems.). I hope that helps. Cheers. ☺
Yes, I know. You are of course correct.. That's why I said it wasn't how it really works at that point in the video and I said the disclaimer at the beginning. I'm trying to keep it as simple as possible.
You don't look for perfect components, you look for: perfect for the job. The last three words are important.
Or you modify your design based on what components are available or affordable. There's an endless battle between engineering, marketing and sales.