It is 1959, you are an EE, confused and undecided whether to…. - Page 1
Forum section: electronics / general

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 30, 2024, 05:17:22 pm
content: …use the familiar Vacuum Tube technology or that pesky newcomer the Transistor, for your new product.No worries, mate! The Electron Tube information Council has printed a dandy new brochure to clarify your doubts. After reading it, you’ll certainly be convinced to use the….the…. What was the name of that Council, again?Anyways, have yourself a wonderful read:https://www.rcaselectron.com/TNT.htmlOf course, any seasoned and intelligent engineer would advocate a hybrid. Using transistors where it made the most technical sense, and tubes everywhere else. Hundreds of successful products were designed this manner, well into the late 1960s and probably early 1970s.I find amusing that a year earlier, Jack Kilby had even demonstrated the NEXT generation of electronics.(*) Note, although the website claims 1959, the brochure’s credits mentioned the publishing date as 1960.

author: jzx
author_rank: Regular Contributor
timestamp: May 30, 2024, 05:21:12 pm
content: I have seen even a TV set with tubes (not only the CRT), transistors, ICs and varicaps ... No leds still, it had incandescent lamps.

author: soldar
author_rank: Super Contributor
timestamp: May 30, 2024, 05:42:13 pm
content: Quote from: jzx on May 30, 2024, 05:21:12 pmSeen them? I made them! Yes, I amthatold.Of course low voltage signal processing parts were transistorized first while high voltage parts retained tubes.I worked in the Telefunken factory in Madrid and we made TVs. Recently I tried to pinpoint the exact location and had a very hard time because the area has changed so much. What used to be industrial is now residential and commercial. Finally I could determine that what used to be the Telefunken factory in Madrid is now a shopping mall called Madrid Rio.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 30, 2024, 05:47:39 pm
content: Quote from: soldar on May 30, 2024, 05:42:13 pmRepaired them, so less old.

author: soldar
author_rank: Super Contributor
timestamp: May 30, 2024, 05:49:18 pm
content: Quote from: schmitt trigger on May 30, 2024, 05:17:22 pmTrying to discredit new technology is, most times, a losing game.I remember TV manufacturer Emerson had ads trying to discredit PCBs. "Our TVs are carefully wired and assembled by hand, wire by wire, with great care..." While Japanese manufacturers went with the newest technologies.Emerson soon disappeared.We had an Emerson TV. The next one was Japanese.

author: globoy
author_rank: Frequent Contributor
timestamp: May 30, 2024, 05:56:26 pm
content: That was a fun read. Thanks ST.How far did tube technology progress in its competition with transistors? I seem to remember reading somewhere about some pretty small and low power tubes.

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 30, 2024, 05:59:29 pm
content: RCA even produced a “transistor killer”, the Nuvistor ultra compact tube.I had a Sansui stereo receiver where the FM tuner section was made with Nuvistors.General Electric also responded with the “Compactron” tubes which had three different devices within the same glass envelope.

author: globoy
author_rank: Frequent Contributor
timestamp: May 30, 2024, 06:14:54 pm
content: Quote from: schmitt trigger on May 30, 2024, 05:59:29 pmI guess the Nuvistor was some of the technology that document in your link was talking about that was coming for tubes with its ceramic spacers. This articlehttp://www.r-type.org/articles/art-150.htmmentions one taking 135 mA @ 6.2V for the heater. I guess that was much lower than traditional tubes but still seems a little crazy today.And the wikipedia article about the Compactron mentions they were making TVs in the 1970s that had tubes, transistors and ICs in them at the same time!So I guess the tube had a reasonably graceful fall from prominence.

author: soldar
author_rank: Super Contributor
timestamp: May 30, 2024, 06:19:11 pm
content: Tubes which had two or three devices in the same tube were relatively common. Two triodes, ecc84 triode-pentode pcl82, pcl84,ecl82, ech84, echXXECH81 was triode heptode used as rf amplifier in heterodyne radio receivers and the triode section used for the local oscillator.I still have my manuals of the timeAlso, I started out in ham radio with tubes. When I started using transistors they were expensive and I blew too many. Tubes were much more forgiving.

author: coppice
author_rank: Super Contributor
timestamp: May 30, 2024, 06:37:16 pm
content: Quote from: jzx on May 30, 2024, 05:21:12 pmIn 1960 the only semiconductors you would find in a TV were some diodes. In 1968 Thorn launched the first colour TVs where the only thermionic device was the CRT. They had dealt with the EHT, using a voltage tripler and 3 diodes that each handled about 7kV each. They had high voltage (about 1600V) transistors to deal with the line scan. They had some simple ICs to help with the signal processing. They even had a class D audio amp. That was quite a decade of change.

author: floobydust
author_rank: Super Contributor
timestamp: May 30, 2024, 06:39:33 pm
content: In the repair shop, I remember Philips colour TV sets circa mid 1970's were pretty strange - they had both IC's and vacuum tubes in them. Mostly horizontal output, HV damper diode and vertical output as I recall.Power transistors were late or too expensive I guess.

author: coppice
author_rank: Super Contributor
timestamp: May 30, 2024, 06:40:05 pm
content: Quote from: soldar on May 30, 2024, 06:19:11 pmBy the time the tube industry started to wind down pretty much the only consumer tubes with a single device inside were power amps and low noise front ends. Even the lower rated power amp tubes included a triode for the pre-amp.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 30, 2024, 06:44:35 pm
content: TV's went through a whole series of changes from tube through transistor to complete integrated circuits, becoming less and less repairable on single component level. For me it was occasional repairs, but a friend of mine did it as a side business. His house was filled with TV's, but eventually he gave up on it as it became less and less profitable.

author: coppice
author_rank: Super Contributor
timestamp: May 30, 2024, 06:45:56 pm
content: Quote from: floobydust on May 30, 2024, 06:39:33 pmI think B&O were the last to make hybrid TVs, in the early 70s. They under-ran their tubes, so they typically lasted for the entire life of the TVs. Having less of a reliability problem than most makers, they had less of an incentive to rapidly strip out all the tubes. Most makers were going through a hybrid phase by the mid 60s. Philips had an all semiconductor chassis, the G8, in 1969, and refinements of that were made for several years, with more and more transistors being replaced by ICs.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 30, 2024, 06:50:19 pm
content: I remember some having modules for the specific functions and it became a swapping of modules game to repair them. Probably beyond the vacuum tube already, but pre integrated circuit. Can't remember makers and models but suspect Philips ones. We are talking 35-45 years ago, so memory faded.

author: coppice
author_rank: Super Contributor
timestamp: May 30, 2024, 06:57:41 pm
content: Quote from: pcprogrammer on May 30, 2024, 06:50:19 pmIn the UK and some other countries the TV business in the 60s was largely a rental business. People didn't want to buy, because the poor reliability of TVs meant they wanted regular easily accessible support. That lead to the early semiconductor TVs being made modular, so the guy you called out could generally swap a module quickly, and take the failed one back to base for repair in a workshop. As technology progressed, the major reliability problem became the board to board interconnects. The Japanese were not burdened by a legacy business. They made TVs a bit harder to fix, but a lot more reliable, using only one or two large PCBs. When people caught on to this, they bought TVs in large numbers, and people like Thorn and Philips, with large rental businesses, faired very poorly.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 30, 2024, 07:13:41 pm
content: Using transistors wasn't a slam-dunk. Until Fairchild invented the planar transistor, transistors were not very reliable and subject to contamination related problems that would render them inoperable (planar transistors use a layer of SiO2 to passivate the PN junctions--mesa transistors, the forerunners of planar transistors, didn't have this protection).Very early in the transistor era germanium was used rather than silicon. Germanium transistors don't work at temperatures above about 65C. There was a famous demonstration by Texas Instruments in 1954 at an IRE convention where a germanium transistor in the audio output circuit of a phonograph was immersed in 65C hot oil. The sound from the speaker stopped. When the germanium transistor was replaced with a silicon transistor, the sound continued without pause when the Si transistor was immersed in the hot oil.By the early 1960s most of the problems with transistors had been solved, and their use in consumer products took off. That wasn't the case as late as 1959, however.

author: jitter
author_rank: Frequent Contributor
timestamp: May 30, 2024, 07:14:08 pm
content: Quote from: schmitt trigger on May 30, 2024, 05:17:22 pmI just had to chuckle when I saw GE's slogan at the end of the ad: "Progress Is Our Most Important Product"...Less than a decade later, some of the components used in the Apollo guidance computers look a lot like SMD to me. "Flatpack electronics" it was called back then.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 30, 2024, 07:21:34 pm
content: Quote from: jitter on May 30, 2024, 07:14:08 pmYes, they were three-input NOR gate ICs packaged as "Flatpacks". There were two gates per package. Unlike common practice today, these ICs were welded to the circuit boards rather than soldered.

author: soldar
author_rank: Super Contributor
timestamp: May 30, 2024, 07:26:49 pm
content: The selenium rectifier deserves to be remembered if only for its stinky smell.https://en.wikipedia.org/wiki/Selenium_rectifier

author: coppice
author_rank: Super Contributor
timestamp: May 30, 2024, 07:27:05 pm
content: Quote from: Sal Ammoniac on May 30, 2024, 07:21:34 pmIt varied. flatpaks were used in various ways. The leads stuck straight out, and were quite hard to bend. Quite a few people made jigs to form those legs to something more like a QFP with long legs, and soldered them down to a PCB. I think welding was mostly used to tolerate the high physical stresses in missiles.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 30, 2024, 07:42:52 pm
content: Quote from: coppice on May 30, 2024, 07:27:05 pmHere's what a PCB in the Apollo AGC looked like:

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 30, 2024, 07:49:31 pm
content: Another advantage of tubes in consumer equipment like radios and TVs was that they were more consumer-serviceable. I'm a child of the 1960s and I remember that when our TV stopped working my Dad didn't take it to a shop or call a repairman. He took the back off the set, removed the tubes, and went down to the local drugstore, which had a tube tester. Replacing the tubes that showed as "bad" on the tube tester usually fixed the problem. He'd only take the TV to a shop if replacing tube(s) didn't work (and that wasn't very often).

author: floobydust
author_rank: Super Contributor
timestamp: May 30, 2024, 08:09:16 pm
content: TI still showing flatpacks forTL072, TL074pg. 58.What's the problem?EE's like to use the latest and greatest parts - but this means they're top price and not always a good, reliable part. Finding that out in production is your basic nightmare.

author: rstofer
author_rank: Super Contributor
timestamp: May 30, 2024, 09:04:51 pm
content: Apple claims their new M3 CPU contains around a 25 billion transistors. That would be a lot of heater current!

author: RJSV
author_rank: Super Contributor
timestamp: May 30, 2024, 10:17:38 pm
content: My guesstimation is, that the Live MUSIC industry was the factor that made Vac Tubes persistent. Even within the various Guitar / Bass Amp manufacturers we debated, and took stubborn stances.Perhaps the better linearity etc of IC parts helped, slowly with partial abandonment of vac tubes.I'm wondering if any SPACE PROBES had used vac. tubes that had....radioactive elements incorporated in each filament. I.E. Cold Filament versions, to avoid the 1 watt of filament heater usually needed?Growing up in 1950, youngsters would often get their start, by way of kind neighbors offering older radios / phonographs, etc.Yay Magnavox ! Awesum WOOD and bent-wood cabinets.Even the knobs were works of art (carved).

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 30, 2024, 10:36:07 pm
content: Here's another perhaps not too well know fact: The first "integrated circuits" were not made with transistors. Tubes with multiple active elements and passive components existed decades before Kilby/Noyce invented the transistor-based IC in the late 50s.

author: Circlotron
author_rank: Super Contributor
timestamp: May 30, 2024, 10:58:59 pm
content: Quote from: schmitt trigger on May 30, 2024, 05:17:22 pmThat publication sounds like all the naysayers on YouTube warning us that electric cars are going nowhere, and that ICE cars are the way, the truth and the life.

author: tom66
author_rank: Super Contributor
timestamp: May 30, 2024, 11:05:17 pm
content: Quote from: Circlotron on May 30, 2024, 10:58:59 pmWorse, it has such promises like heaterless tubes (did they ever happen?) and micro-integrated tubes the size of transistors... hmm seems unlikely given we can fit billions of them on silicon now. A bit like the people convinced hydrogen cars or synfuels will be the future, rather than the technology that obviously currently works.

author: coppice
author_rank: Super Contributor
timestamp: May 31, 2024, 01:11:26 am
content: Quote from: Circlotron on May 30, 2024, 10:58:59 pmThe GE advert about tubes for computers is deranged, but the book is actually reasonably balanced. It was targeted at designers building products for the next couple of years, not the long term. In 1959 a designer could choose between expensive fragile germanium transistors that failed when you got the junction beyond about 60C, and tubes. Even in the mid 60s there were more new products using tubes than transistors. Even some portable things, like car radios, were still being introduced with tubes well into the 1960s. Its easy to look back and see the extent to which the tube business was on borrowed time, but it wasn't that obvious that things would change as fast as they did looking forward.

author: coppice
author_rank: Super Contributor
timestamp: May 31, 2024, 01:19:14 am
content: Quote from: tom66 on May 30, 2024, 11:05:17 pmHeaterless tubes did exist, and were very small, but their performance was poor and they didn't catch on. They might have been too expensive, too. Heaterless tubes were revived at the beginning of the 80s, being fabricated using standard semiconductor processes and silicon. There was real excitement about possible high performance using them, but people like Mitel perfected fast isolated CMOS, and that blew them away.Quote from: tom66 on May 30, 2024, 11:05:17 pmIn 1959 the idea that semiconductors with even a few thousand parts on a small die was science fiction. Do you think anyone working at that time could forsee where we are now?

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 31, 2024, 01:24:44 am
content: Other than CRTs, vacuum tubes usage persisted on high power RF devices, like a radio or TV broadcast transmitter.I ignore whether this is still true.

author: coppercone2
author_rank: Super Contributor
timestamp: May 31, 2024, 01:58:04 am
content: Quote from: tom66 on May 30, 2024, 11:05:17 pmimagine it did not have the FET thin gate problem. if it could handle the power some how, a small size vacuum tube would be accepted in power electronics, and possibly simple circuits made more robust (i.e. PSU basic logic / telemetry (feedback opamp/comparator etc). For the power side of things, even basic TI (thermionic) CPU to do operations involving power factor stuff would be welcome IMO. Ceramic composition resistors are basically a improved 1840's technology and they were seen as welcome for power electronics that needs to be robust. 10% tolerance and 4$ for a resistor but there is reason to buy it because its tough and low on parasitic effects.

author: Andy Chee
author_rank: Super Contributor
timestamp: May 31, 2024, 02:31:43 am
content: Quote from: schmitt trigger on May 31, 2024, 01:24:44 amTube transmitters are being slowly phased out. When a tube transmitter reaches end of service life, it is now almost guaranteed to be replaced with a solid state transmitter.Although they are lower power per "package", SS transmitters can be easily cascaded, thus providing scalability in power output, as well as redundancy.Also SS transmitters do not have the filament heater electricity costs, many transmitter sites looking to reduce operating costs as much as possible.

author: globoy
author_rank: Frequent Contributor
timestamp: May 31, 2024, 02:55:36 am
content: Quote from: coppice on May 31, 2024, 01:19:14 amImagine going back in time and handing a 1 TB Micro-SD card to one of the designers of the 1956 IBM RAMAC 5 MB drive. Imagine what someone 68 years from now might hand us.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 31, 2024, 03:54:51 am
content: Quote from: floobydust on May 30, 2024, 06:39:33 pmIn Australia, we went to colour in 1975.All the Colour TVs available were fully solid state in the year or so leading up to "C day", as were the normal colour picture monitors we used at the TV transmitter site where I worked.We had a Philips k9 as our "domestic" type off air receiver.There was a huge Blaupunkt valve(tube) colour picture monitor we had hanging around various places for some years, which hardly ever worked.During one of its brief working periods it was fobbed off on us at the transmitter site.Strangely the Tektronix RM529 waveform monitors were filled with tubes.

author: RJSV
author_rank: Super Contributor
timestamp: May 31, 2024, 04:09:52 am
content: Circletron:'NAYSAYERS', yeah, thanks for the label (I guess). I think you meant some of us that just make things up, more based on emotion.Try my method: Obtain some of your smarts by listening to folks like the U.S. Secty of Transportation. By his own words, as he explains the real lack of charging stations built up to now, (vs stated goals).My jaw dropped, literally, when he stated how many built so far, in his federal program.'8' charging stations, as of May 26.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 31, 2024, 04:18:30 am
content: Quote from: Andy Chee on May 31, 2024, 02:31:43 amAnalogue TV & Broadcast transmitters had extremely long lives, with the 1959 vintage Marconi TV Tx at ABW2 finally being replaced in the early to mid 1990s. I can't remember the exact date, as I had changed jobs to TVW7 down the road, & just remember the dead Marconis being transported past on a big truck.They were replaced with NEC Tx, which used all solid state in the Aural Tx chain & solid state up to & including the PA driver in the Vision Tx, followed with a tube PA.This worked well as the same solid state PAs could be used in both sections.We had the same NEC setup at TVW7.In the years leading up to the change to digital, new all solid state transmitters began to pop up at various sites, preparatory to being used in that service.They were "liquid cooled" which was to most of us, "a blast from the past", as mainstream water cooling of tube transmitters had disappeared before we had joined the workforce.

author: RJSV
author_rank: Super Contributor
timestamp: May 31, 2024, 04:18:53 am
content: Oh wait, sorry; I just could not believe my own words, so I googled Pete Budagieg statement, from couple days ago:"7" PV charging stations completed, under Biden's 3.5 $ billion plan to establish charging networks.(Confusing because there are other chargers, when you Google that)

author: EPAIII
author_rank: Super Contributor
timestamp: May 31, 2024, 07:07:58 am
content: A TV set with tubes? WOW! You mean like the RCA that my dad brought home one day. Did yours have a ROUND screen? A real wood cabinet? Did the TV repair guy have to come by every two or three months with his caddy full of tubes? One where all the controls were ON THE SET: no remote. You had to get up to change the channel or volume. You had to adjust the VERTICAL and the HORIZONTAL from time to time or if you changed the channel. Well, when your city finally got a second channel, that is?Well, I went through all that. Oh, and then there was the Howdy Doody show. In black and white, of course.Then I got a job in TV and met tube type TV transmitters. Now I was the guy changing the tubes. We pulled each and every one of them on a weekly basis and measured their gain with a tube tester. It was graphed and when the line took a down turn by 5 or 10 percent, out it went. That's how you keep a transmitter with 50 or 75 tubes on the air with only rare outages while in use. And for those rare outages you had a second transmitter with the filaments kept powered up and ready to go at the press of a couple of "Plates" buttons. And it had another 50 to 75 tubes that also had to be tested weekly. The midnight shift guy got that job. Guess who!At one station the tube salesman came around every six or eight weeks to be sure we were happy with his company's tubes and service. He always bought a nice lunch for me and my assistant at a beach front restaurant/bar in Ft Lauderdale.And the TV cameras. They were originally a nightmare of tubes. When color came along, it was even worse. You could start a show with three cameras that, after an hour or two of work, were fairly well matched in color. But a half hour later one was green, another purple, and the third blue. And you had to correct them on the fly. TUBES!I was never so happy as when the 2Ns took over. I suspect the design engineers were the same.Quote from: jzx on May 30, 2024, 05:21:12 pm

author: tggzzz
author_rank: Super Contributor
timestamp: May 31, 2024, 07:40:55 am
content: Quote from: globoy on May 31, 2024, 02:55:36 amBased on the last 40 years: smaller faster cheaper, but fundamentally the same.But maybe not: Dennard scaling has hit the long-predicted brick wall, so perhaps there will finally be some interesting innovation.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 31, 2024, 08:26:40 am
content: Quote from: schmitt trigger on May 30, 2024, 05:17:22 pmQuote fromhttps://www.rcaselectron.com/TNT.htmlQuoteThat's woke propaganda: yet another attempt to associate white men with something bad, plus, that's an entirely fabricated story, so a lie.If you think that's not propaganda in disguise, then replace "white men" with "jews", and read that paragraph again. Now you see what is wrong with that link?

author: soldar
author_rank: Super Contributor
timestamp: May 31, 2024, 09:56:14 am
content: Don't overreact. I agree that the woke point of view (white men, cigars, etc) is unnecessary but the fact is that a bunch of people, white men because that is who were in those positions those days, decided to create "The Electron Tube Information Council to tout the virtues and utility of electron tubes".And it is a strategy that has been used by many groups interested in continuing to sell what they make when they see a competing technology coming down the road.In general it is a losing strategy. Companies that are rigid tend to fail. Companies that are flexible and adapt and change tend to succeed. We all know many examples.And it is not only products and technologies but entire countries. American automakers deprecated Japanese cars like American electronics manufacturers deprecated Japanese products.Today we see the same with Chinese products. It's propaganda, it might work a little bit in the short term but I think in the long term it will fail.

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 31, 2024, 03:03:43 pm
content: Quote from: Andy Chee on May 31, 2024, 02:31:43 amDo they still operate in Class C? Or is it Class D?

author: RJSV
author_rank: Super Contributor
timestamp: May 31, 2024, 05:57:23 pm
content: Ah ha; The 'WOKE' quotation comes from some other web site! I read 'Paunchy' as a 'FATTY' put-down, again the foreign quote (not an EEVBLOG forum thread).Those 'fatty', or 'paunchy' person put-downs are a trigger for those overweight. Good thing THIS forum seems clear of any constant reminders, of things sifting down to the'Lowest Common Denominator'.That's a math term but I think it meant that (now) everyone must function at a low enough level, so as not to offend (the blithen idiots).How about substitute words, into the current roll call of US University demonstrators;Paunchy demonstrators took over the Admin building today.And, Who did the underline and bold print the term 'White Men' ?I know of one of those, in power right now (although he dont know it). Yeah, him. The one who voted to incarcerate blacks...Ask Kamala, about men conspiring, to block any further upward promotion. She's excluded from movement, as plans are laid, in back rooms.Great,...now you've baited me to refute crap from OTHER forums.....(sorry)

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 01, 2024, 12:05:01 am
content: Quote from: tom66 on May 30, 2024, 11:05:17 pmhttps://patents.google.com/patent/EP0503638A2/enDon't think there was an actual product but seems the physics is there.Then there's the Thermionic Integrated Micro Module.Orhttp://www.hts-homepage.de/Silizium/Silizium.html

author: vk6zgo
author_rank: Super Contributor
timestamp: June 01, 2024, 04:09:52 am
content: Quote from: RJSV on May 31, 2024, 04:18:53 amDoesn't PV refer to "standalone" Photo voltaic (Solar cell powered) stations, rather than ones connected to the "grid"?As the grid in the USA is extensive, most charging stations would be supplied from that.There are likely more "standalone" solar powered stations in Australia, as we do have gaps in our grid.

author: vk6zgo
author_rank: Super Contributor
timestamp: June 01, 2024, 04:20:20 am
content: Quote from: schmitt trigger on May 31, 2024, 03:03:43 pmCertainly the last generation of analog TV transmitters operated in Class B, as linear amplifiers.The old tube Tx used class C, high level modulated with high power video signals.Low level modulated transmitters using superheterodyne principles allowed much of the transmitter circuitry to be interchangeable between Tx on different channels.

author: RJSV
author_rank: Super Contributor
timestamp: June 01, 2024, 04:48:29 am
content: Sorry, my mistake!Was thinking 'EV' or 'Electric Vehicle', but I used 'PV' by mistake.So, it should have said:'number of EV charging stations, built so far, under 3.5 $billion dollar program'

author: Andy Chee
author_rank: Super Contributor
timestamp: June 01, 2024, 10:10:52 pm
content: Quote from: schmitt trigger on May 31, 2024, 03:03:43 pmThis video may be educational:https://youtube.com/watch?v=LOAoG5GwAEQDon’t let the title AM fool you. The later discussed techniques can be used for any arbitrary signal, DRM, DAB, or old skool AM. This is what makes modern solid state architecture flexible.