IF Frequency

[@eliashellberg8214]

Without a doubt, the best video on youtube for explaining this. Thank you so much!

[@5vart5ol]

They say Jazz is the magician of music. Are you the magician of teaching? Cause you bend and mend the knowledge to fit into any filter we student may have. Well done and thanks!

[@alnoorr8108]

Great Tutorial, We did this in Grade 12 in the Electronics Class, in 1975

[@JP-vg8vl]

thank you for this video. I literally cannot find any video about IF frequency that explained very well like this

[@abhinav788]

I really liked the part where you told about how the old radio model worked and what was the flaw in it. Such connection is very good to understand I think. Thank you!

[@theengineer9910]

Glad I found this vid cause an analog design book I'm reading spoke of IF which I didn't know about

[@LL-ue3ek]

Thank you so much! Plain and to the point!

[@TB-nz4kf]

God Bless El Rushbo!

[@stevefoster2700]

I've watched a couple videos on IF to understand this and finally someone said the local oscillator frequency changes. Light bulb on...thank you!

[@mah6786]

Really well explained, thank you. It turns out a spectrum analyzer uses the same architecture.

[@TheGmr140]

Be sure to see my other videos, many are funny and interesting.

[@kengerace]

Well done. Very easy to understand. Thanks for posting!

[@Radioaddict2200]

I like your background music selection.

[@michaelshansen7070]

WELL DONE! I finally understand fully! 😄

[@mplmpl7780]

Many thanks going for intermediate ham licence and this helped

[@alexismotet9327]

This is good. Nice history part. Thank you.

[@Xyz12391]

Thank you! You are literally the best!

[@syntaxerror2409]

Thank you so much for this, this helps a lot for my upcoming report about IF circuit.

[@mariofilippi3539]

Very good explanation, thanks very much.

[@paulmaine6433]

You are presenting good material. Please avoid political comments like your comments on Rush. It’s off putting to some.

[@bakeronews1]

Nice tutorial. Thanks!

[@acestudioscouk-Ace-G0ACE]

Thanks for this, I understand now!

[@kw5kw]

I like Rush

[@joaopedrolourencoaffonso2168]

Thanks very much! Saved my life!

[@railgun1935]

excellent explanation but plz no back ground music. p.s I love music in general

[@zulhendrazul3844]

God bless you....thanks a lot.... very nice explain....

[@arelenas]

Great video! Thanks!

[@preuton]

Why is it cosine and not sine?

[@TheGmr140]

Can be either

[@indrashispowali]

this video is also an advertisement of uni-ball pen.... which is pretty good actually

[@sirashp9118]

Thankyou, that was a short and sweet explanation

[@zhixianjin8754]

If I understand correctly, for the upper convertor, we need to get cos(a+b) out of the mixer. All we need to do is use a IF filter at high frequency. Therefore, the only difference between down convertor and upper convertor is the IF filter passing frequencies.

[@TheGmr140]

Yes correct

[@TekCroach]

The difficulty was not designing a filter with low bandwidth in RF. The problem is that you would have to make it vary to cover the entire spectrum of interest.

[@raulcrudele1]

Great video. Just a comment, for AM radios, the local oscillator runs a frequency ABOVE not BELOW desired tuned radio. If you want to tune 530 - 1700 with an IF of 455, then the local oscillator runs from 985 to 2155. In FM, typical offset is 10.7 MHz. Regards!

[@TheGmr140]

Thanks for watching, i just really trying to get folks to understand IF frequency

[@TheGmr140]

Thanks for watching, i just really trying to get folks to understand IF frequency

[@eswnl1]

The example here is low side injection. But you can have high side as well.

[@klaus-udokloppstedt6257]

​@@TheGmr140thanx @TheGmr for explaining what IF is and what it's reason. I'm just trying to learn these 'radio'-stuff and it's terms to get ideas why my vintage receiver is quite noisy when stereo is active. and thanx to @raul too, for making the connection to the 10,7MHz. 🤝

[@s199h]

Doctor , Why do we need to convert the received RF signal to IF signal?

[@TheGmr140]

To filter out unwanted signals, and amplify the signal you want

[@s199h]

@@TheGmr140 Thank you doctor so much

[@Sabari-gd3fw]

Could any one please explain what is span frequency? i.e. 10 khz mentioned in this video

[@TheGmr140]

Span is the signal bandwidth. Am signals have 10khz bandwidth. So span is equal to signal bandwidth.

[@Sabari-gd3fw]

@@TheGmr140 Yes now I understood about span.. Thanks for your response

[@theoryandapplication7197]

thank you very much

[@7MPhonemicEnglish]

Best explanation I've found but can be improved by showing actual components and electrical diagram to explain how the LO and mixer works.

[@omsingharjit]

continue your great edu work .

[@trejohnson7677]

best music

[@kristhompson8112]

Nice BG Jazz with Dave B , Not sure how you get that past KZbin these days, Really appreciate your explanation, Now I have I.F in the bag I think, cus got a bit lost at the end , Ill try shoe-horn this information into understanding the Wadley Loop set up in my Dads old valve communications receiver.

[@ahmedmuhammed6905]

That all what i need, thanks

[@omsingharjit]

Can you make rf spectrum analyser using crt tunner and Arduino or using other available radio module from frequency of 80Mhz to arround 1Ghz plz

[@TheGmr140]

for cheap. rtl-sdr is the way to go, i believe someone wrote a app that turns the rtl-sdr into a sweeping spec ana like you want. rtl can cover 80Mhz to 1GHz

[@omsingharjit]

@@TheGmr140 i know that but it's not Available here inindia

[@omsingharjit]

very nice and simple explanation

[@Reclaim68]

Good explanation!

[@chuahtc]

Well explained. Thanks!

[@SolarDrew]

Dave Brubeck... do you copy?

[@chrisw2281]

brilliant video!!

[@KittyFloof]

Love your videos. Can you do some on LNA, PA, and Mixer?

[@TheGmr140]

i'm more of a dsp guy, but i'll make a video that goes over these parts and how we use them. thanks for watching.

[@prasadvindla8960]

what is difference between this down conversion v digital down conversion?

[@TheGmr140]

Good question, DC is often by rf mixers to shift down to some IF frequency. DDC is a step after a ADC in firmware to shift digital signal to zero hz

[@microreniassance2929]

So, just to be clear; when I change the frequency of the local oscillator only the RF that appears from the LNA that when subtracted from the the LO equals the resonant frequency of the IF circuitry will be that signal that is passed to demod. So, the tuning dial is actually indicating the frequency in the RF feed (1.5MHz) that when subtracted from the LO gives the IF resonant frequency. If I understand this correctly. So to listen to broadcasts at 1.5MHz, the LO is tuned via the tuning dial to the frequency that when 1.5MHz subtracted from it gives equals the 455KHz IF frequency. Meaning the LO would be tuned at 1.955MHz to receive 1.5MHz on an IF chain with a 455KHz resonance frequency. Is this correct? Great Video. I may actually be beginning to understand how it works.

[@TheGmr140]

correct, tuning radio is changing lo frequency

[@themightyquinn100]

Great video! So the filter only picks out the 455 kHz and not the 1525 kHz?

[@TheGmr140]

That is correct

[@felipenogueira30]

Thank you so much!

[@aprilmiranda3157]

Super like 💕💕

[@jmohamed87]

Thank you !

[@bensas42]

Thank you so much for the explanation! What is the choice of IF Frequency (455 KHz in the example from the video) based on?

[@TheGmr140]

Just a typical value used in radios

[@microreniassance2929]

Thanks to the IF for filtering out the RL idiots!! Great video, by the way!

[@ahmedamraniakdi2143]

Big thanks

[@brucecorbettn9bh398]

Good job.

[@raidensama1511]

Take 5 and RIP Rush Limbaugh.

[@steelcantuna]

Rush Limbaugh... Yeah man really... Some people just "can't handle the truth." God, Heaven, Hell, the whole truth & nothing but the truth, turns people off!!!!!!!!!!!!!!!!!!!!! They just don't won't to hear it.

[@microreniassance2929]

what a joke.

[@preuton]

Why is it called a multiplier? It's the sum and difference between lo and rf.

[@TheGmr140]

2 cos A cos B = cos A - B + cos A + B

[@phillipneal8194]

Yes. But I don't want to listen to 990khz. I want to listen to 20meters !!! What do I do ?

[@TheGmr140]

Change the lo

[@ΑβάσιμοςΠρίγκιπς]

chilly dude chilly

[@VargRETURNS]

so the frequency we pick on a radio is not the exact frequency being transmitted, its just the local oscillator frequency? Its proportional?

[@TheGmr140]

It's the TX frequency. Local oscillator change radio station you tune in

[@VargRETURNS]

@@TheGmr140 tx?

[@TheGmr140]

@@VargRETURNS the signal the radio demod is the if frequency. The lo frequency shifted the TX frequency to the IF frequency

[@ahmetserdr2920]

Why we dont convert to baseband? What iş the advantage of using IF

[@TheGmr140]

the IF signal is then often sent to a A/D then after the A/D, the signal is shifted to DC by means of a DDC. please see my video on DDC

[@ahmetserdr2920]

@@TheGmr140you mean in order to get IQ Signal, am o right?

[@TheGmr140]

@@ahmetserdr2920 yes, this would then be the baseband iq signal

[@TangoMikePapa]

Dude you are goood

[@7MPhonemicEnglish]

Are you telling me that the IF is a constant 455KHz?

[@TheGmr140]

depends on design. most radios use 455khz or 10.7Mhz , the idea is you can then make a narrow and stable filter at a fixed freq. and you just change the LO to tune into different signals.

[@7MPhonemicEnglish]

@@TheGmr140 Ok, thx ya and some use 465 MHz. I'm just trying to understand how the output stays at the designed designated frequency. My understanding about AM is that the audio is encoded in the wave amplitude, so as long as that passes on to the new freq. all is well. I just don't understand how a wide array of freq inputs all get output at one constant freq. I would expect frequencies equal to X minus 455 or X plus 455. I don't know how what's going on electronically.

[@irfan_antennas]

What happens when LO and RF are same?

[@irfan_antennas]

frequenceis.

[@TheGmr140]

hello, we want the IF to be 45Mhz, so adjust LO to make that happen. since the upconverter is really only for hf freq, one should place a 10Mhz lpf after the loop antenna

[@irfan_antennas]

@@TheGmr140 Thanks for the reply. Actually can you tell me what happens when the LO and RF frequencies are same?

[@TheGmr140]

@@irfan_antennas this is called a zero-IF radio. when the rf and lo are the same, the IF freq is zero. the sum is filtered away. this is how the hackrf and some other sdr work. more info: google: zero-IF reciever

[@irfan_antennas]

@@TheGmr140 thank you so much.

[@omsingharjit]

how IF signal further process how it demodulate like IF signal from Tv Tuner how it Further Process into Audio Can i just use Germanium Diode in series with If to get Audio ? Or Somthing needs like Saw !!

[@TheGmr140]

If sends signal to demod circuit. IF ensure only one signal be at demod circuit

[@omsingharjit]

@@TheGmr140 what components used to demonstrate why saw filter are used can simple diode demodulate it ?

[@MohammedTubail]

Bro......that's how ODU works in Microwave Transmission Engineering (under Telecom) Thanks

[@sam-kx3ty]

you explained downconversion more than you explained IF frequency but good job.

[@coffeecuppepsi]

If frequency what?

[@spusha01]

cos(A+B)+cos(A−B) =2cosAcosB

[@TheGmr140]

Thanks, in mixer hardware however the power levels are different due to lo drive. The real take away is the sum and difference frequency

[@mikeghfawaz4547]

Intermediate Frequency

[@liamausden8248]

I thought it was cos(a)cos(b) = 1/2[cos(a+b) + cos(a-b)]

[@TheGmr140]

you are correct. real take away is a mixer, which makes sum and diff frequency. but yes you correct.

[@liamausden8248]

@@TheGmr140 Thanks for the reply. Good video!

[@kootaru_]

я ничего не понял(

[@mdesm2005]

I like Rush, so I stopped at 1:00 and rated a thumbs down.