a science related question
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Vishal Gupta
Microsoft MVP
I also many times faced it.
Whenever my cellphone is near to the radio or TV, a strange sound( like beep) starts coming and I can know in advance that a new call or SMS is coming in a few seconds.
This problem seems to occur ,when recieving a page for an incoming call. Cell phones also cause the radar detector to go nuts.
Whenever my cellphone is near to the radio or TV, a strange sound( like beep) starts coming and I can know in advance that a new call or SMS is coming in a few seconds.
This problem seems to occur ,when recieving a page for an incoming call. Cell phones also cause the radar detector to go nuts.
siriusb
Cyborg Agent
Mobile phones produces high energy waves for communication. The energy is enough to activate those tiny fancy lights that you can attach to the back of a mobile phone. But it decays inverse squarely so that on reaching the tower it is only enough to be heard.
I guess this wave is acting on the voice coils of ur speaker and producing currents which in turn is driving the speaker.
Call initialization can take a lot of energy, so you may actually see the interference in the crt monitors and speakers seconds before ur mobile phone starts to ring.
I guess this wave is acting on the voice coils of ur speaker and producing currents which in turn is driving the speaker.
Call initialization can take a lot of energy, so you may actually see the interference in the crt monitors and speakers seconds before ur mobile phone starts to ring.
siriusb
Cyborg Agent
bharat_r said:
In airplanes, an unsheilded wire might get current when there should be no current in there if a mobile phone is place near it. But it has to be so close to the wire/equipment to start any serious damage.
But when airplane is so high in the air, ur cellphone tries to increase its power output to maximum. If all the passengers' cell phones did that, the airplane wud go haywire. Same thing is applicable to hospitals' icq (or something like that) rooms.
pradeep_chauhan
Cyborg Agent
The noise or interference we here in the speakers / TV / Stereo is from the transmissions made from the hadset that are placed next to these devices. The signal originating from the cell is strong and its harmonics create the strange beeps we here. Also these noise are due to the transmissions from the cell phone rather than the tower as the signal strength is much higher as compared to the transmissions made from the tower/BTS.
huzaifa b arab
GetUserTitle()
I think it's due to the similarityies in the signal frequencies whichm disturbs everything....
kalpik
In Pursuit of "Happyness"
Hmm one point id like to clear, a cell phone wave's power is not enough to induce current in the speaker. Actually, it does not interfear wid the speaker at all! It interfears wid the electronics. There are two types of cellphones used in India: GSM and CDMA. As u all must have noticed, nothing is disturbed when u get an incoming call on a CDMA Phone, only the GSM phone interfears. GSM allots a different frequency to each subscriber to differentiate btw different subscribers. When not in use (as in just switched on and standby) to save battery power, the phone is not in contact wid the tower (that is why if the phone is in standby, and u remove the batt widout switching off, the phone becomes unreachable instead of showing switched off). So whenever the tower gets the call or an SMS, it sends an ENABLE signal to the frequency of the cell phone concerned. The cell phone then "Handshakes" wid the tower by returning the signal (This is the signal that creates the beeps). When the signal reaches the tower, the call is established (Thats why it takes a few secs before the phone rings) And if the signal is NOT returned by the mobile, it is rendered not reachable. When u switch off ur phone, it sends another signal to the tower, signalling that it has been switched off (So the tower does not waste time searching). That is how a GSM mobile works.
Whew! Long post, hey but remember, dont ask for source, cuz i wrote each n every word myself! Hehe
Whew! Long post, hey but remember, dont ask for source, cuz i wrote each n every word myself! Hehe
kalpik
In Pursuit of "Happyness"
Here's how CDMA works. Hehe!
CDMA allots the same frequency to many phones, only the information transfered is encoded, and only the correct phone can decode it. It operates on some frequencies (dunno exactly) but it does not interfear wid electronic items (hence no disturbance to other electronic items). One thing though, CDMA waves have "Scrambling" effect. Try this: take a cheap quality FM radio, tune it to some frequency (so that u can hear a particular channel) then take a CDMA phone near it, and make a call. The FM radio will stop working and u wil have to re-tune it. Hehe.
CDMA allots the same frequency to many phones, only the information transfered is encoded, and only the correct phone can decode it. It operates on some frequencies (dunno exactly) but it does not interfear wid electronic items (hence no disturbance to other electronic items). One thing though, CDMA waves have "Scrambling" effect. Try this: take a cheap quality FM radio, tune it to some frequency (so that u can hear a particular channel) then take a CDMA phone near it, and make a call. The FM radio will stop working and u wil have to re-tune it. Hehe.
expertno.1
Technomancer
if i keep my mobile near my monitor..it vibrates....why ? give ve me physics point of view
This thread has been going on longer than I thought it would.
A short answer to the OP's question would be that radio (electromagnetic) waves radiating from the phone is causing interference with the computer's audio system. But that's fairly obvious.
The problem with trying to give a more detailed explanation is that we have to go into electronics in some depth and that may not be very appropriate for this forum. It may also not be very helpful to someone without some background in electronics. Let's see what we can do without invoking too much technical jargon.
Someone else has already stated that it must be the response signal from the phone and not the signal from the tower that's causing the interference. That's true. Under normal circumstances, the signal from the tower is too weak to cause interference. The signal from the phone is also too weak to directly cause the speaker to vibrate unless perhaps it's placed very close to the voice coil.
Most electronic circuits involve amplification, that is, a weak voltage or current goes into one end (input) and a stronger version of that voltage/current comes out at the other end (output). Any fluctuation at the input comes out as a much stronger fluctuation at the output. In many cases, the fluctuation is intentional and carries meaningful information or data.
After the signal has gone through enough amplification, it is made to go through a non-linear section that extracts the information carried. This is called "detection". This process of amplification and detection takes place inside a radio, TV or cellphone.
But sometimes the amplification-detection process is accidental. The signal from the phone induces a current in some part of the audio system's amplification chain. It gets amplified and detected and finally emerges as sound from the speaker.
@expertno.1 : when you say "it vibrates", do you mean the mobile or the monitor display ?
A short answer to the OP's question would be that radio (electromagnetic) waves radiating from the phone is causing interference with the computer's audio system. But that's fairly obvious.
The problem with trying to give a more detailed explanation is that we have to go into electronics in some depth and that may not be very appropriate for this forum. It may also not be very helpful to someone without some background in electronics. Let's see what we can do without invoking too much technical jargon.
Someone else has already stated that it must be the response signal from the phone and not the signal from the tower that's causing the interference. That's true. Under normal circumstances, the signal from the tower is too weak to cause interference. The signal from the phone is also too weak to directly cause the speaker to vibrate unless perhaps it's placed very close to the voice coil.
Most electronic circuits involve amplification, that is, a weak voltage or current goes into one end (input) and a stronger version of that voltage/current comes out at the other end (output). Any fluctuation at the input comes out as a much stronger fluctuation at the output. In many cases, the fluctuation is intentional and carries meaningful information or data.
After the signal has gone through enough amplification, it is made to go through a non-linear section that extracts the information carried. This is called "detection". This process of amplification and detection takes place inside a radio, TV or cellphone.
But sometimes the amplification-detection process is accidental. The signal from the phone induces a current in some part of the audio system's amplification chain. It gets amplified and detected and finally emerges as sound from the speaker.
@expertno.1 : when you say "it vibrates", do you mean the mobile or the monitor display ?
These problems are common in GSM & TDMA systems.
Here are some exrepts i found on the net.
Some Links
Health Physics Society: Cellular Phone and Base Station
How Stuff Works: I've noticed that I am not allowed to use my cell phone in airplanes or in hospitals. Why are these prohibitions in place?
PDF: Fundamentals of Interference in Wireless Networks (This has the physics )
PRIVATE LAND MOBILE INTERFERENCE COMPLAINTS (just in case you need it)
Moto V551: hourly interference with computer speakers? (a long mailing list. you will need patiance to read. but worth reading)
Here are some exrepts i found on the net.
Some Links
Health Physics Society: Cellular Phone and Base Station
How Stuff Works: I've noticed that I am not allowed to use my cell phone in airplanes or in hospitals. Why are these prohibitions in place?
PDF: Fundamentals of Interference in Wireless Networks (This has the physics
)PRIVATE LAND MOBILE INTERFERENCE COMPLAINTS (just in case you need it)
Moto V551: hourly interference with computer speakers? (a long mailing list. you will need patiance to read. but worth reading)
navjotjsingh
Wise Old Owl
Is any mod looking here. Almost all users have posted more than one times in succession. Why can' they edit their posts. that's how their post counts are so large.
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