[SOLVED] Why AM has lower Frequency than FM ???

[Jigar 4 Electronics]

Hello Everyone,

I just come to know [Through a book of Microwave & Radar Engineering. by, M.Kulkarni (1st chapter, 2nd page)]
that :

" The signal from an AM Radio station is 1MHz and the signal from FM radio Station is 100 MHz. "

Can anyone please share some knowledge with me regarding the Frequency selection of AM and FM.
I mean, Why AM (amplitude Modulation) has Lower Frequency than FM (Frequency Modulation) ?


In addition to this,
I also like to know why and how " AM has a smaller bandwidth Because of which it can have more stations available in any frequency range."
I got the above statement from here : https://www.diffen.com/difference/AM_vs_FM

I've already read these much : https://answers.yahoo.com/question/index?qid=20090208031220AATd1kV things to know my answer but didn't get satisfaction and why so I am asking here.

Thanks for your time.

 

[jiripolivka]

The difference is technical and historical. Before ~1940, all commercial radio transmissions were AM, over medium-wave bands through short waves, 2-30 MHz.
With the introduction of FM, the modulated spectrum was much wider: for AM, 10-20 kHz is needed, for FM, >150 kHz is required. Due to that the spectrum up to 30 MHz was full of AM signals, FM transmission was done at > 40 MHz. Later, we have the standard FM range of 87-108 MHz, 76-108 MHz in Japan.
Coordination of the frequency spectrum is a global problem, with an intent to guarantee the service without interference.

 

[Syncopator]

In addition to this, I also like to know why and how " AM has a smaller bandwidth ...

That is generally true only in the f.m broadcast band. If audio fidelity is not particularly important, e.g. it is not intended to transmit music, f.m. transmissions are often limited to 5kHz peak deviation.

 

[davenn]

Hello Everyone,

I just come to know [Through a book of Microwave & Radar Engineering. by, M.Kulkarni (1st chapter, 2nd page)]
that :
" The signal from an AM Radio station is 1MHz and the signal from FM radio Station is 100 MHz. "
Can anyone please share some knowledge with me regarding the Frequency selection of AM and FM.
I mean, Why AM (amplitude Modulation) has Lower Frequency than FM (Frequency Modulation) ?

You are working under a very false assumption you are relating AM and FM to a frequency range when in reality its just a modulation mode.
The is a quite common mistake
AM and FM can be used on any frequency from pretty much one end of the spectrum to the other
My transceiver radio can do AM, FM and SSB on any freq within its legal coverage from 1.6 MHz to 1300MHz and if I want to I can inject digital signals from my computer and transmit them over that same range
if you want to go super high in frequency you can even AM or FM or digitally modulate a laser

cheers
Dave

 

[Jigar 4 Electronics]

Thanks to all experts for reply... I understand your answers but I didn't get the reason cleared about this sentence :

"why and how " AM has a smaller bandwidth Because of which it can have more stations available in any frequency range." "

Can you please give me some more details here ?
Thanks again for your time.

 

[davenn]

Thanks to all experts for reply... I understand your answers but I didn't get the reason cleared about this sentence :
"why and how " AM has a smaller bandwidth Because of which it can have more stations available in any frequency range." "
Can you please give me some more details here ?
Thanks again for your time.

That still totally depends on the use of the mode. if its FM Radio Broadcast and particularly stereo ( as is normal these days) then the FM bandwidth can be very wide upwards of 150kHz. for digital TV even wider, upwards of 8MHz depending on the if its standard definition, hi definition etc.

The FM that is used on commercial and amateur radio tranceivers for voice comms can be as low as 5kHz

So you see you cannot make a blanket one idea covers all statement line ...

"why and how " AM has a smaller bandwidth Because of which it can have more stations available in any frequency range."

because it isnt true, its totally dependant on the needs of the user for a given situation.

Dave