What is Fm: Definition and 113 Discussions

FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. Therefore, FM is used for most broadcasts of music or general audio (in the audio spectrum). FM radio stations use the very high frequency range of radio frequencies.

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  1. wukunlin

    How does fm actually suppress noise

    So I have been taught about FM having noise supressing characteristics, but in that particular course the lecturer told us not to worry about it as it is out of the course syllabus. So I tried to look up on the details on the internet but all I keep seeing is that FM supresses noise but I...
  2. Z

    Designing a low-power FM radio transmitter

    hello i have been given six weeks to design a low-power FM radio transmitter for my project however there are no lectures for this course so i have to do the research on my own. so far from researching on the web. i have found that a simple radio transmitter may consist of a number of stages...
  3. G

    Use an IC to tuner fm transmitter

    I'm making one of those simple FM transmitters. It uses a variable capacitor to tune. According to the writer of the tutorial, it is difficult to tune the circuit and RF is generally finicky. How would I use a microcontroller to tune the circuit? Thank you, -GiTS
  4. N

    Build a FM Radio Receiver: What Do I Need?

    hello i am new, i thinking to make a fm radio receiver but i don't know what i need (capacitor, oscillator etc) can someone help me with more knowledge than me ? if you have link or something else that maybe help me is welcome. i search the internet but i don't can find anything that suit in my...
  5. Y

    Design a FM tranmitter step by step (advanced questions)

    Guys, from circuitstoday.com I researched, I understood ig picture of a basic FM transmitter. there should have basic blocks like audio amp, modulator (oscillator included), radio amp and the anttena. suppose I want to build a FM transmitter, what is my first step? step1 says I choose 0.5m...
  6. A

    Difference between FM and AM waves?

    Just curious about the differences between AM and FM radio waves. Any info is appreciated, thanks.
  7. C

    FM vs AM Broadcast: Advantages & Disadvantages

    Hi, Could somebody tell me what's the difference b/w FM ( frequency modulation) and AM (amplitude modulation) broadcasts? Also please mention the advantages and disadvantages of both ... I'll be thankful :)
  8. R

    What Distinguishes AM from FM Transmitter Circuit Designs?

    I have been studying multiple AM and FM transmitter schematics trying to distinguish the differences in the circuit that create either am AM (amplitude modulated) or and FM (frequency modulated) RF signal. I have hit a road block as I am unable to see any significant differences between the two...
  9. N

    Understanding an FM transmitter circuit

    Homework Statement . I am just trying to understand this cicuit a little better. Especially the right half, I know that the left half is just acting as an amplifier but I'm not sure how the right half works. Also how is the frequency being modulated here? The attempt at a solution. I...
  10. T

    Calculating Speed to Reach 1.11 fm from Oxygen Nucleus

    Homework Statement The oxygen nucleus 16O has a radius of 2.91 fm. With what speed must a proton be fired toward an oxygen nucleus to have a turning point 1.11 fm from the surface? Homework Equations Kinetic energy = 1/2 mv^2 Potential energy = 1/4(pi)Enot * q/radius min The...
  11. S

    Why the discrepancy in muonic H Bohr radius? 285 fm or 256 fm?

    Some places say (including this paper) claim the bohr radius of muonic hydrogen is 285http://ethesis.unifr.ch/theses/downloads.php?file=LudhovaL.pdf Many more peer reviewed papers say it is 256 fm, or 255 fm though. (search for '256 fm muonic' in teh googlez). So who is right? And more...
  12. M

    FM Modulation: Solving Problems with 400KHz and 40 Amplitude

    Hello, So I was studying for my exam and came across this exercice we did in class and which I really don't know how we got the answer. It says that if we have a FM with a carrier frequency of 4MHz, and the bandwidth is 400KHz, what is then the maximum deviation.. The answer is 200KHz...
  13. K

    Need help in FM Receiver project

    As title, my lecturer had given me a project which to design a Analog RF Walkie talkie which in Frequency Modulation and carrier can be between 50Mhz - 200Mhz. I had actually designed the transmitter part but quite confuse in receiver part. Can any master can actually give me some general idea...
  14. L

    Wavelengths of a laser pulse and inductance in tuning of an FM radio

    Homework Statement Pulsed lasers used for science and medicine produce very brief bursts of electromagnetic energy. If the laser light wavelength is 532 nm, and the pulse lasts for 37 ps, (a) how many wavelengths are found within the laser pulse? (b) How brief would the pulse need to be to...
  15. D

    What is the relationship between pressure and velocity in fluid flow?

    if we consider fluid flow, then bernoulis equation says that pressure must reduce when velocity is high.What is the direction of pressure when fluid is in flow? When fluid is stationary then pressure varies in vertical direction. It acts in downward direction on account of gravity. Means it is...
  16. S

    FM vs AM: Which Radio Wavelength Is Bigger?

    it has been a while. i need to know which wavelength is bigger FM radio or Am radio?
  17. V

    First Project - Simple FM Radio/Receiver made Complex

    Hey everyone, I'm taking on a fairly difficult first project. It's based around a schematic called the 'Radio Shack Special,' which is a simple, super-regenerative radio receiver that is configured to pick up FM signals (It is supposed to be capable of both AM and FM). The FM receiver's...
  18. D

    Anyone know how I can build a FM radar gun?

    Well here are a couple of things I would like to know. Thanks in advance! how to build a Frequency-Modulated Radar gun. or how to build a Frequency-Modulated transmitter and reciever or where i can get either of these :D Thanks again!
  19. M

    Powerful FM Transmitter Kit for Sale - Affordable Prices

    Hello folks. I want to buy a powerfull Fm Transmitter kit. Where can i find one at reasonable price? Cheers..
  20. D

    Improving FM Radio Reception: Tips & Techniques

    Homework Statement I bought an FM radio mono kit. After I assembled it, it works. But I want to know how to have a clear reception or signal and to acquire more stations. What should I do? Any tips or techniques? does the coil affects the signal? Homework Equations The Attempt at a...
  21. T

    Using PLLs as FM Receivers: Why It Isn't Possible

    I don't understand why a PLL alone can't be used as an FM receiver. I've got a project showing how PLLs are used and I'd like to use an FM transmitter (which I have a schematic for) transmitting wirelessly a signal that is demodulated by the PLL a few feet away. Seems pretty simple, where I set...
  22. S

    FM Transmitter Circuit (Please Explain working)

    Hi.I have got this circuit for a low cost short range FM transmitter but I am unable to understand the working and functionality of the circuit.Please help me in understanding the working.What I know is that its working as a VCO(voltage controlled oscillator) when input (through electret mic) is...
  23. H_man

    Frequency components of FM wave

    Homework Statement I wanted to show that a particular wave is composed of the 4 frequencies W = W0 +/- W1 +/- W2 The equation for this FM wave is y(t) = Acos(W0t+W1COS(W2t)t ) I tried showing the different frequency components by performing a Fourier transform on the equation y(t)...
  24. K

    Need clarification about FM demodulation

    For the Frequency modulation the carrier frequency will change with respect to data. but i need to transmit the modulated carrier at 93.5MHz means what i need to do.
  25. G

    Question on finding the Fundamental Period of a periodic FM signal

    Homework Statement s(t)=13*cos(2000*pi*t + 100*sin(8*pi*t)) Determine the fundamental period of this signal, i.e., the shortest period. Homework Equations x(t)=A*cos(2*pi*f(c)*t + a*sin(2*pi*f(m) + phi)) A=13; f(c)=1000; a=100; f(m)=4; phi=0 Inverse Euler's - A*cos(omega*t + phi) =...
  26. M

    Could a FM transmitter amplify a 200 nanovolt signal for a gaussmeter?

    I am trying to amplify extremely small signal(around 200 nanovolt) from a coil of wire on a ferrite to make a gaussmeter, I've seen some FM transmitter schematics online that I want to connect this signal to, Would a FM transmitter be able to work with a signal this low? I tried amplifying...
  27. O

    What Are the Steps to Design an FM Transmitter?

    Please I want to know how fm transmiters are designed. I need help
  28. O

    Designing FM Transmitters: Tips and Techniques for Selecting Component Values

    I want to know how to design fm transmitters. That is how to select appropriate values of the components. I need help
  29. H

    Comparing AM and FM Broadcasting: Research Ideas

    Hey all I have to do a massive physics report on the topic "a comparison of Am against FM broadcasting." What are some topics i could research and compare. Cheers HSV
  30. turbo

    Commercial FM radio is driving me nuts

    My Sony 400-CD carousel died last week, and I have been waiting all that time for a replacement to arrive. My collection (about 75% of it fits in that player) is a mix of blues, rock, country, country/rock (think Poco, Buffalo Springfield, etc), bluegrass, R&B, etc. I unloaded all my CDs from...
  31. M

    Calculating Wavelength of Radio 4 FM & Explaining Loss in Deep Valleys

    Homework Statement Radio 4 transmits on FM at a frequency of 92.5 MHz Calculate the wavelength and use it to explain why listeners in deep valleys cannot pick up radio 4 FM. Homework Equations The Attempt at a Solution
  32. I

    Communication Problems (Filters, BW, Bit rate, FM)

    Homework Statement A 1kHz analogue signal is to be encoded using 8-level Pulse Code Modulator. This specification results in a bit rate of 5.5K bits/sec. The signal is to be transmitted over a 1 km distance with a 10kHz bandwidth on a Frequency Modulated, F.M., Carrier. The carrier frequency...
  33. A

    Design FM Receiver Circuit | 144-146Mhz Frequency Range

    I want to design a fm receiver circuit for the frequency range of 144-146Mhz.Kindly suggest me a suitable ic for the same.
  34. C

    What Damage Can Infrared Rays, Radar Waves, FM Waves, etc. Do To The Body?

    What damage to the body can infrared rays, radar waves, FM waves, TV waves, "shortwav What damage to the body can infrared rays, radar waves, FM waves, TV waves, "shortwave" waves, and AM waves do? I have to do a physics project on causes of cancer, based on a physics standpoint. I have an...
  35. F

    Avoid Poor Sound Quality with FM Transmitters

    A quick one for you sparkies... There are a ton of FM transmitters you can use to pipe your iPod or other device over your FM stereo. There is one thing in common to the three units I have tried that is very annoying. I have noticed that there is very poor sound quality for the higher...
  36. J

    Can You Clarify the Grounding and Power Source in this FM Transmitter Circuit?

    Hello everyone, I'm relatively new to dabbling with electronic circuits, so I decided to build my own FM transmitter using a circuit I found on the internet. The schematic has been attached as an image file. However, there are a few things I'd like to clarify. What exactly does the 'ground'...
  37. K

    Reception of distant FM radio broadcasts

    1. An aluminum airplane is flying west, parallel to the ground, at 350 m/s. The Earth's magnetic field produces a downward component of 8.30 x10-5 T at that point. For the purposes of this question, treat the wing as if it was a conducting rod. a) What is the magnitude of the potential...
  38. B

    Zero-Crossing Demodulation of FM signals

    Hey guys, For school I have to study the zero-crossing demodulation method of reconstructing an FM signal. So far what I've been reading has been confusing me a bit and I have a few questions to ask: 1) How does a LP-filter act as a "time averager" for a train of impulses? 2) Does the...
  39. J

    Can You Broadcast Internet Radio Locally with a USB FM Transmitter?

    Hi I usualy lissen to radios on internet, and i would like to be able to hear it everywhere in my house, rather than just when i am on my pc. Does this exist : a Frequency Modulator that i can plug by USB to my pc, and broadcast localy (like a 250 meters range) my internet radio or any...
  40. E

    Exploring Digital Signals over FM for FSK

    Hi, I'm thinking about transmitting digital signals with FM. The effect I'm trying to achieve is FSK. Can I just feed the digital signal to the input of the FM transmitter? With FSK the carrier is frequency modulated with 2 frequencies, but since the digital signal has infinite bandwidth...
  41. S

    FM Radio Transmission Distance

    I have a simple question - but I somehow doubt there is a simple answer. 1) I would like to start a small, non-commercial, home transmitted FM Radio Station - mostly for fun and as a hobby. I have seen an 18W transmitter for a reasonable price. I live on relatively flat land in the country...
  42. G

    How Does Each Component Function in an FM Transmitter Circuit?

    Hi, I am attempting to figure out how an FM transmitter I'm building works. I was wondering if anyone had some suggestions on a resource for transistor circuits or just has some ideas of how to go about figuring it out. If anyone is interested, here is the schematic...
  43. M

    Design & Construct FM Radio Receiver 87.5-108MHz

    The objective is to "design and construct an FM radio receiver" that is able to tune to commercial FM radio broadcast channels spanning from "87.5 MHz to 108 MHz", and to produce audible demodulated output. can anybody help me with a simple circuit for this assignment with proper values for...
  44. S

    How Can You Design an FM Radio Receiver to Favor One Station Over Another?

    Homework Statement Designing an FM Radio Receiver. You enjoy listening to KONG-FM, which broadcasts at 96.6 MHz. You detest listening to KRUD-FM which broadcasts at 96.5 MHz. You live the same distance from both stations and both transmitters are equally powerful, so both radio signals produce...
  45. A

    Find an FM Radio station's wavelength, frequency given

    [SOLVED] Find an FM Radio station's wavelength, frequency given Homework Statement An FM radio station broadcasts at a frequency of 101.3 MHz. What is the wavelength?Homework Equations Vsound = 343m/s @ 20 deg C λ = v/fThe Attempt at a Solution I used the formula λ = v/f and got something...
  46. DaveC426913

    AM vs. FM Quality: Is MHz the Key Difference?

    Correct me if I'm wrong. I've always taken it on faith that the switch to frequency modulation from amplitude modulation resulted in the much better quality signal and listening experience we have today. Modulation of the frequency is likely less susceptible to distortion than is modulation...
  47. F

    Explaining FM Signal Spectrum on a Spectrum Analyzer

    I'm looking for a "physical" explanation (or as close to one as I can get) for the displayed spectrum of an FM signal on a spectrum analyzer. I'm using a sinusoidal carrier of 200 MHz, a sinusoidal modulating tone, and a deviation of 5 KHz for my question. Lets say I use a very slow rate...
  48. S

    Need help building FM Transmitter

    So I'm trying to get my fm circuit to work. I've taken the design from the website below. http://cappels.org/dproj/FMdist/fmdis.htmhttp://img217.imageshack.us/img217/6839/fmdis3un4.jpg My current issue is that the circuit works, but only when hooked to a DC transformer. I get a signal of ~...
  49. F

    FM Spectrum Questions - Answers Needed

    I have a few questions regarding the spectrum of FM... 1. What is the equation that predicts where the sidebands will occur in an FM signal given a certain FM rate and deviation? 2. If I have an FM signal with a rate of 16 KHz and a deviation of 5 KHz and I look at the signal on a spectrum...
  50. R

    Bandwidth of FM Signals: Carson’s Rule

    A satellite telemetry link operating in S-band uses frequency modulation to transmit the value of an analog voltage on the satellite to a receiving Earth station. The voltage has a range from -1.0 volts to +1.0 volts, and a maximum frequency of 1000Hz.The FM modulator on the satellite has a...
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