Fun With Analog Multipliers: Squares, Cubes, and VCAs
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- čas přidán 14. 07. 2024
- Need a frequency doubler? Want to plot a cubic function on your 'scope? How about a square root extractor, or a voltage controlled amplifier? Analog multipliers like the AD633 make all this (and more) a snap! www.analogzoo.com/2016/06/fun-...
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I know this video is kind of old, but it brings back memories for me. Around 15 years ago, I used the AD633 in a air flow sensor product that I did the electronic design for.
At the heart of the product was a differential pressure sensor that measured the pressure drop across a venturi orifice as air flowed through it. It needed a root extractor circuit to calculate raw flow, and another AD633 for a multiplication step to derive mass air flow at any given pressure.
I did this all in analog to keep the response time of the product below 1mS, while also keeping the costs low. If I did something like this again today, I would probably just use a micro-controller. Back then, (circa 2005) I found that there weren't many MCU's that had 12-bit A/D converters, and there were even fewer that also had 12-bit DAC's.
The AD633 just worked too well not to use it, and they only cost $1.33 in 2005. I just checked the price and they have gone up significantly. AD has good stuff but their prices are salty.
Thank you so much for these explanations and graphics. They're so insanely helpful for somebody like me starting EE from a completely non academic place.
I'm starting to build an analog synth cabinet and this video has given me some great ideas
These are great - wish you were still making videos!
Thanks
Some inspiring discussion here. Uses for these multiplier chips that 1 might not normally think about.
Cool device. Very well explained. I was planning to use one in a electronic load with constant power mode.
Many thanks for all these great videos!
Man your videos are awesome! I haven't heard of this AD chip before. I'm designing a compressor and a modular synth right now and it might get useful! Even though I chose an opto resistor in a voltage divider for the VCA (non linear) in the compressor. Thanks!
Execelent videos! Thank you and please keep on!
Very interesting! I did a year of analogue electronics at school with the dear old 741 op amp, but it would have been much more fun if we had had such lovely toys as this to put in our circuits! If I had this equipment I would build a circuit to generate the Lorenz attractor, though I believe that doesn't display well on modern solid state oscilloscopes.
Really great video. Please make more videos. Im in love with Electronics :)
Whoever made this chip is a guru in analog.
Absolutely beautifully explained 👌👌👌👏👏👏👏
Very Nice and Informative video. For high Frequency Multiplication we can use MC1496 (AM modulator) i have made 5 Mhz A.M radio with it. AD 633 works upto 1Mhz only. MC1496 is more cheaper and frequency upto 300 Mhz
Hi can you help? Looking a way to multiply a sine wave...I mean...to put 40hz at input and at output to have 80hz full sine wave without modifications on his form... can I do that with this kind of ic's?
MC1496 is extremely non-linear, linear operation happens only in the region of sub couple tens of mV signals. AD633 is highly linear, even for large signal. You can not replace a AD633 with a simple MC1496 gilbert cell multiplier. At least not very easy.
Pretty sure diode ring mixers can multiply two variables, as is the case in basically any AM radio from the previous century.
Yes, you can use even the AD633 as a mixer. Mixer is a multiplier - ideally. Real mixers are more opimized for low level RF signals, unlike the AD633 (and such), that have very good linearity even for large signals.
TIL that adding some component in the _feedback loop_ of and op amp will allow the output to reflect the inverse operation of that component.
Thank you for the info 👍👍
Great video, liked the drawings. My only suggestion for improvement would be instead of saying 'imagine this opamp isn't here', remove it in your drawings like the cool way you added the labels and the diode.
Very interesting!
Could you use the Z offset input as a way to bias the multiplier to run off a single supply?
Brilliant video. The only problem is the analog multiplier ICs are comparatively expensive
excellent video as always. i wanted a bit of advise as you seem like the perfect guy. i have got the opertunity to buy a HP 8558B 1970 made all analog 1.5Ghz spectrum analyser. the problem is the front frequency set knob is a big multi geared pot which is broken. is it still worth it for $50?
I suppose that depends on how badly the pot is broken, and how easy/expensive it would be to fix. For $50 though, I'd be tempted to just get it and see if you can't fix the pot if that's all that is wrong with it. Just watch out for shipping costs on that old gear!
Its local pick up so no shipping. I not really need a spectrum analyser yet but as you said $50 and an all analog circuitry makes it super interesting i am buying it. The pot its smashed in badly, i wonder if i can fit a modern 10 turn pot instead...
which are the power levels and the schematic of the circuit, slaudos from Colombia c:
Great video, but sadly they are far from cheap. Nowadays they cost 14 $ a piece. For people around where i live, cheap is below 1 $.
But anyway, it's good to know these things exist. Thanks for the video.
for the freq' dbl' appn. ... save the result of a 2khz sin wav. and run it thru same ckt ... repeat .
2 --> 4 , 4--> 16 ... talk to us about any distortion in the product with these repeat doublings.
and show us the spectrum along the way if your scope has that as one of its math functions.
the '633 spec's cite noise , nonlinearity and error values in table 1. could you also show us what
form they take as seen on your scope . for many of us it will be the first time the details in
a data sheet come to life
Does anyone have a suggestion of a simple rudimentary analog implementation of multiplier circuit AD633 on a breadboard without operational amplifiers? I've seen the diagram, it uses OP amps, but I've got only transistors, resistors, diodes, capacitors.
Do you have Bob Pease's EDN magazines?
What source do you study from?
perfect
Can you please upload the schematic?... In my case as soon as I turn on the supply the AD633 ic gets burn up
How to devide analog signals?
Hi when you say it double its frequency at the output..you mean the double with the full wave without modifications?...
Try to get de square of a sin(x) function on a graphic calculator. As the result go below 0 it becomes negative, va a negative square gives a positive. So, effectively you're generating a positive representation of both the negative piece and the positive piece, getting twice the frequency, but yeah, it will pull the classic '-1 to 1' range of a sine function to '0 - 1' range. It will still be a sine wave, though.
Well, now I know that the AD633JN frol Aliexpress that I bought are fake, those only heat up and do nothing. Very helpful video.
can you make a video for me please of how to make a crystal oscillator on a breadboard and make it variable frequency ,and i mean a crystal collpits oscillator, and yes i saw your video on collpits oscillator but i want to see a video on how to biuld it on a breadboard and make sure it works
For crystal Oscillator , there is one simple solution which i have used is my project. I brought a 30 MHz 4 pin Crystal oscillator , it gives a square wave output (Normally used with micro-controllers, sine wave is also available), from a square wave(Bi-polar) we can get a sine wave by simply connecting a LC narrow band pass filter in series with the crystal oscillator to filter out it 1st harmonic frequency.
Hi, complete newbie here... Was wondering what potential issues one can run into if one tries to use this for division via a negative feedback loop?
NVM, should have watched till the end
can you run it in reverse and get an extremely fast cube-root?
It's possible to make a cube root circuit, but you need two AD633 chips. And it might be difficult to keep it stable.
So it just work in 1st quadrant only.
Can the multiplier do 0 x 0
I tried to run the circuit and the AD633 gets very hot, it's not stable!!!
The AD633 shouldn't get warm at all with the circuits I used. Sounds like maybe a power or mis-wiring issue?
@@Analogzoo sorry for the late, the problem was the AD633 that i used in my probes was fake :c
Hello, can you please tell me how you solved the heating issue
Sweet, not taught in the technician course.
Try SA612. It's 10 times cheaper :)
If you try to duplicate these results with an SA612 I think you will be sorely disappointed! Even in a simple frequency doubling application, an RF mixer like the SA612 will produce horrific distortion due to the significant harmonic output of the mixer (in RF applications this is generally not a problem since the unwanted frequency content is simply filtered out).
Although many RF mixers at their core use a Gilbert cell multiplier, just like the AD633 that I used in this video, they are *not* the same as an analog multiplier. In an RF mixer application, it is undesirable for the amplitude of the local oscillator to have a significant effect on the amplitude of the IF output, otherwise small changes in the LO amplitude would cause unwanted amplitude modulation of the IF output. This is why RF mixers use the Gilbert cell in "switching mode" such that the LO simply multiplies the RF input by 1 and -1. This is also why using an analog multiplier as an RF mixer is generally a bad choice. RF mixers also do not have very stringent DC offset requirements like analog multipliers do...there's a reason analog multiplier ICs are more expensive!
+devttys0 thanks for explaining ;)
You're welcome! I do wish it was as simple as getting a cheap SA612...analog multipliers are a bit on the expensive side! :\
+devttys0 Hey, I have an idea! I have couple of old soviet analog multipliers 525PS2 laying around. I could send them to you, and if you have time and inspiration, you can compare them to AD633 and tell us about differences between them. Can it be interesting for you?😃
That would be awesome! Shoot me an email: webmaster [at] devttys0 [dot] com
wow that chip is 10 € on mouser, I wanna get prototyping but I'm to afraid to fry it. guess it gotta simulate it first :D
7:00 so... we can see that analog computers don't believe in imaginary numbers
but what happened to this channel :-(