More about Notebooks and T-Shirts…Super-Heterodyned Receiver (one of Armstrong’s MANY contributions)Brief Preview of RF “Tran-ceivers”(Transmit and Receiver)Blocks for SPAM Receiver (HO#1 p.12a)A Quick Look at BW...(including preview of FCC perspective)Motivation about Multipliers--based on our discussion of AMA Trivial Multiplier…[and Preview of Distortion Issues]Preview of an IC “Mixer”Looking inside the IC…A word about Transistors…The most basic multiplier (called the “transconductance multiplier”)A (really) practical implementationReview of Current Mirror (w.BJTs)The basic BJT “Laws” and their applicationsIn terms of the two Ic’s and vid…What do Collector Currents look like?And now for more details about IEEAnd using the above results in DICWhat about voltgages Wave-Forms?(here we’ve “over driven” vid with respect to VT)Reference for Currents…Two_Quad vs Four_Quad…(huh?)A Classic Multiplier ICDetails of the ICWhat is a Four-Quad Multiplier Anyway?Derivation of 4Q Results--defining Ic’sHow to get the final “Tanh” at OutputsPhysical argument about connections(plus x plus=plus; minus x plus=minus; minus x minus=plus)Way to improve input range for bottom differential pair (versus 612 limits)An Equivalent way to do it with single REPractical implementation in the 1496Results comparing range for 612 vs 1496Armstong, Antennae &Wireless1Lab Notebook from DeForest(key in Major Patent Battle)More about Notebooks and T-Shirts…Dear Lab NotebookLab 1--They say things are a bit different down herein the basement.Like how your biological clock no longer works. How the boiling point of water is slightly elevated. And how light slows down just a bit.Lab 2--Hey, this lab wasn’t that bad! (It’s all downhill from here.)Lab 3--On Valentines Day, I made for my significant other a witty valentine card. I used phrases like “dB my valentine” and “let’s resonate.” I’m not sure why I got slapped.Lab 4--I stayed really late in lab last night, so I couldn’t avoid falling asleep during Dutton’s lecture. I dreamed that he was delivering our Commencement address, and he said that we had to impedance matchour college years with the next stage of our lives.Lab 5--My doctors tell me that somehow the presence of lead in my blood is three times the federal health limit, and if I don’t stop whatever I’m doing, I will become mentally retarded. (Obviously, it’s too late.)Lab 6--I had a horrible nightmare that nothing worked, and the TAs told us to rebuild the whole damn thing. Wait, was that a dream?Final--If we scream and no one cares, do we make a sound?You need to get and keep a hard-bound lab notebook. This is stuff that is absolutely KEY for defining and protecting IP. When yougo for a job inteview after graduation and you show them your EE133 Notebook (and IF you’ve done a careful, diligent job), youmight find it to be a major asset (=“job experience”)The DeForest story is amazing. He and his arch rival John Armstrong (inventor of FM and Hetero-dyning) had a pitched battle over IP. Unfortunately, this “B-” lab book was used as “evidence” even though DeForest couldn’t actually explain his “invention”2Super-Heterodyned Receiver (one of Armstrong’s MANY contributions)AntennaRFLO(Local Oscillator)RFMixerAudio AmpSpeaker(Audio Output)RF FilterVFO(Variable Frequency Oscillator)IF Filter“Tune” both filterand VFO at the sametime…giving outputof mixer ALWAYSat Intermediate Freg.IF at FIXED Freq.and therefore LO Freq.is also fixed in takingoutput of IF down to“basedband”Advantages of Super-Het:•Tuning/Image Rej. Decoupled from detection•IF filtering can be optimized and also reused (I.e. many AM stations, converted to single IF)•MUCH easier to work at IF vs. directly at RF (especially at high frequencies)One more pass on the Receiver side, this time giving a quick preview of how your commercial radio receivers work…As you will certainly see (by doing in Lab #5), down conversion to a nicely controlled and well-defined intermediate frequency (IF) is very useful.In commercial radio this is at 455KHz (and for your projects it will be a bit lower). It is at a FIXED frequency for ALL stations.That means that the stage before the IF needs to have it’s localoscillator (LO) “tuned” (using a Variable Frequency Oscillator=VFO) such that the resulting spectrum (I.e. the difference term from the law of the cosines) ends up exactly at the IF.Then, when the spectrum (your station’s signal) modulated about the IF is multiplied times the IF/LO, the signal is NOW at baseband.The above slides and discussion are definitely a “fast forward” on things we will spend the rest of the quarter working on. This discussion is purely motivational in terms of block diagrams of transmitters and receivers….3Brief Preview of RF “Tran-ceivers”(Transmit and Receiver)AntennaRFLO(Local Oscillator)MixerDecodingAudio AmpSpeaker(Audio Output)Unwanted Signal(I.e. station at “Image”)“Down Converted”SignalRF LO Image freq.Solution:Use “Filter” to“Reject Image”Your modulated FMsignal--carrier + voiceWhat do RF signals look like in the frequency domain and how do we get them down to “baseband” where we can hear the information?In the simplest case (90%+ of what EE133 is about) the RF band signal will be a carrier with sidebands…the sidebands are the information.To get the RF signal down to baseband we use our good friend, the law of cosines: Now the math is the same but we are trying to only keep the difference termsthat bring our signal back to “baseband”. (and filter out the sum terms)What’s also shown in the figure is an unwanted “image” signal.Unfortunately, the multiplier will do its job on ALL signals present, unless we filter them out. If we don’t filter out the “image”…Both the local oscillator (LO) frequency minus our RF and the Image Freq. Minus the LO will BOTH end up in the same “down converted” frequency range.Comment: in this example we did NOT convert the modulated signal all the way to zero frequency. That is, we down-converted by a different frequency than we up-converted. We’ll be talking about this more in the demodulationlabs--especially for FM [This NEW frequency will be the “IF”]Cosω1t()Cosω2t()=12Sinω1t −ω2t()+ Sinω1t +ω2t()[]4Blocks for SPAM Receiver (HO#1 p.12a)BNC toANTXOLNAMixer(SA 602)IF AmpPLL(LM 565)BNC