How a Lock in amplifier works

This video explains how a Lock-in amplifier can pull out tiny signals which are buried in noise.

[@zaphodcuk]

Best lock-in detection explanation on KZbin. Many thanks!

[@MohammadKareem-kd2pz]

This was fantastic explanation. I looked many videos for a simple explanation about lock-in amplification, but this one was really great. Thanks a lot

[@wackojuggler]

This was an excellent description. Thank you!

[@markkennedy9767]

Great explanation. Very interesting concept

[@stephenklein969]

great explanation, thanks!

[@theobruelhart5974]

great video, appreciate your work!

[@rodneybernard4959]

Very well explained

[@ARoque-hhhhh]

great explanation (and love your voice) thank you!

[@PawlTV]

Great video! Thank you, Mark! :)

[@yongqishi6445]

Fantastic!

[@alexwang007]

And since multiplying two signals at the same freq but at a 90 deg offset results in an average of zero, you would also multiply your signal with a copy of the reference but at 90 deg offset, and thus results in I and Q outputs

[@boratsagdiyev3936]

Correct

[@guitar0wnz]

Saved my life man

[@jinsubpark7317]

Thank you

[@basmaal-ghali9174]

thank you

[@vijaymenon5738]

Thanks for this video, just what I needed!

[@VandalIO]

Very cool !!!!!

[@bernardocaio6331]

Muito bom!!

[@shivanshawasthi27]

thanks

[@georgemihai9612]

This was a great introductory video! Could you tell us something about how do RollOff and TimeConstants play a role in signal processing ? Thank you,

[@markschnittker4770]

Increasing the time constant will average out the lower frequency components. This is analogous to narrowing the bandwidth of the frequency range that will pass through.

[@jasonchonko]

Great work, Mark. Not sure if you remember me, but we worked together when I was at Keithley instruments. I hope you are well

[@markschnittker4770]

Jason, Sure I recall. I dont think that Keithley ever offered a Lock-in, but if they did I think it would have been a good one based on their other offerings.

[@jasonchonko]

@@markschnittker4770 Nice to catch back up. No. They don't. I'm with Lake Shore Cryotronics and the new M81 does have lock in measurements: www.lakeshore.com/products/categories/overview/material-characterization-products/measureready-m81-synchronous-source-measure-system/measureready-m81-synchronous-source-measure-system?M81-Branded&M81&hsa_kw=m81&hsa_mt=p&hsa_tgt=kwd-389603167127&hsa_src=g&hsa_ad=632730062849&hsa_ver=3&hsa_cam=18806881853&hsa_net=adwords&hsa_acc=3884305122&hsa_grp=143470127415&gclid=EAIaIQobChMIltWFoPDq_AIVJcmUCR0ypgrSEAAYASAAEgKbdPD_BwE

[@TheCitygear]

Thank you! Now, I've understood about IQ demodullation.

[@akhil6095]

Is there any good ref book for studying lock-in amplifiers?

[@MrFleischFloete]

Whats the X and Y Values that one can read from the Lock In?

[@ikramkhan11692]

can you please tell where can I get that ad630 module shown in your slide?

[@markschnittker4770]

The chip is the AD630, but many companies make low cost lock in amplifier boards from the AD630 chip and simply call them an AD630 lock in amplifier. I have purchased them from Ebay and Amazon. If you do a web search I am sure you will find some. Note that they are not nearly as sensitive as a bench top tool and also they are not adjustable for phase or time constant, but they do work quite well if your signal only 2-3 orders into the noise. If your signal is 6 orders below then noise, then you would probably need the much more expensive SRS lock-ins. If you get a chance to use an SRS, then you will find they are fantastic tools which cost much more, but are 3-4 orders of magnitude more sensitive than an AD630 lock in.

[@mantoshchawla3060]

Can the Reference Signal be a DC signal when the signal to be measured is AC signal