Collection Mobile Tips & Tricks M.Irfan

[josher]

Collection Mobile Tips & Tricks M.Irfan

How to repair dead phone

Problems or trouble typically found on mobile phones can be categorized into
Three damage categories, namely:
1. Software Problem category
2. Hardware Problem category
3. Problem Category his SW and HW
Phone problems and solutions
1. Total dead cell phone
Mobile phones exist three kinds of die total, die total because of
· Die alone,
· Total death due to falls, and
· Death total for the taxable water.
a. Total death because death itself.
Handling:
The first can be done early steps following
- Remove the battery and plug in again, or try using another battery and try turn it
- Check the battery connector and try the press to see the level of flexible or not,
replace damaged when new.
- Connect the charging of the phone, when the indicator on the phone in and still will not turn on, then obviously you can not live on mobile phones because of interference from IC PA (Power Amplifier). After IC PA revoked your mobile phone can turn it on again. And so no signal will be installed a new PA IC.
- When the tide does not exist and charging indicator on the phone still does not want to live on should be conducted further tests using power supply. But there may also have an ugly tin on the PCB, remove the IC PA solution, then clean the tin on the PCB where IC PA stick, replace the old IC PA, HP switch, it must be a flame.
Examination with power supply:
Necessary power supply on a scale of 1 ampere ampere (A) or 1000 mA.
With the aim that the examination can be more easily and clearly.
The steps are as follows:
- Connect the cable from the power supply to the mobile phone battery connector of at least three wires, with a negative sequence, BSI and positive. (Black, green and red)
- Navigate volt power supply at 3.6 V (or in accordance with tolerance Hp-0.5 V)
- Mobile phones in the state of OFF, and press the button on
- If the current (amperage) in a digital ampere dipower supply pointer when the button is pressed on, it just means there's still a problem on its hardware (HW), it is necessary to check the components on / off until the battery.
- When the ampere when the button is pressed on, up about? 50 mA, then the problem that occurs is a matter of software (SW), then you need to do is re-programmed HP (flash) or program is upgraded to higher versions.
b. Total death from falls.
Handling:
- HP may not be tested by using the power supply, but HP should be dismantled first, heated, and repositioned back to the location / position of the components has changed as a result of HP fell.
- After that, the new HP using the power supply should be tested to determine damage to the Hardware (HW) / Software (SW).
- Most likely a damaged components as a result of the fall is the HP PA IC / IC Power.
c. Total death due to hit the water.
Handling:
- For taxable HP water is also the first time should not be tested by using the power supply, because the risk of short circuit occurs between the components in water, but must first HP divakum, heated, or by first diblower given IPA cleaning liquid, can also use the grain silica to absorb the water that existed at HP.
- After HP confirmed it was dry, then we should use the power supply to determine the damage occurred on the Hardware (HW) or Software (SW).
- At HP's exposed to water, usually there is damage to HPnya accessories.
2. Total die because of IC phone UI.
In HP's case like this then requires test equipment that is power supply.
The steps are as follows:
- Connect the power supply on the phone, give the voltage (volts) equal to 3.6 V (or in accordance with tolerance Hp-0.5 V)
- At the time the phone is in off state, refer to the power supply needles amperes will increase by 100mA.
- The phone will start, LED lights, VIBRA vibrate.
Handling:
- Remove the IC UI, then turn on the phone.
- Then there is the display on the LCD mobile phone "Insert SIM Card".
- Put new IC UI.
- Turn on the phone, the phone will work fine.
3. Total dead cell phone because the CPU IC.
To determine whether the cell phone because the IC die total CPU is as follows:
- Give the voltage (volts) on the phone by using the power supply of 3.6 V (or in accordance with tolerance Hp-0.5 V).
- At the time the phone is not turned on, the needle ampere silent, but if the phone is switched on then the needle will rise 100mA amperes.
Handling:
- If the IC CPU is still in good condition, then we only need to heat the IC CPU by using a blower, but if the CPU IC is damaged, then we need to replace with a new CPU IC. Before we replace our CPU IC must first have the anti-hot glue and liquid glue crusher anti-heat, because the CPU IC is protected by anti-heat glue, after we destroy the anti-hot glue, then we can heat (blower) CPU IC for a new replacement. Similarly, after we replace it with a new CPU IC then we need to give more anti hot glue to protect the new CPU IC we replace it.
4. Total dead cell phone when we call.
For testing we use the power supply by way of:
- Connect the phone with power supply, give the voltage (volts) equal to 3.6 V (or in accordance with tolerance Hp-0.5 V) on the phone.
- Needles amperes will not move when the phone is still in a state of death.
- We turn on the phone and then used to make calls, then the needle will show the number of amperes above 400mA.
Handling:
- Replace with a new IC PA, after re-testing was done as above, if the needle test results show the figures below 400mA amperes, the phone is in good condition.

 

[josher]

How to Work HandPhone

1.3 Introduction

Before you go any further about repairing mobile phones, of course, you must first understand the working principle of mobile phones in order to simplify the process of analysis of damage to the phone.

In this chapter will be discussed in broad outline and in general, because the development of mobile technology today is always changing.

Center 2.3 command processing input / output.


3.2.1 Command input.


Each time you make an order to the phone, for example typing an sms, play games, changing phone settings, voice recording, photos, and others. All of the above command is a command from the mobile phone users, which can pass the command-like device: keypad, camera, infra red, Bluetooth. All input commands will be accepted by the CPU, then the CPU will process all the input commands. CPU can process all the input commands based on system operating data contained in the IC flash. IC flash will store the input data when commanded by the CPU, RAM, while the IC will accept data from the CPU for a while.

3.2.1 Command Output.

CPU will provide overall command of the command input, the command from the CPU is very universal in the overall mobile phone navigation system, for example: giving the order to display graphical information on the LCD, giving orders to the UI (vibrator, buzzer, LED), gives orders to the power supply voltage to meretribusikan , and others.

3.3 Power Supply


3.3.1 Power up / down (On / Off)


The process to turn the phone is not the same as ordinary electronic circuits such as radio, etc. TV. At almost the same phone system with a computer, where the process does not turn on or turn off by disconnect power to the power supply. In the actual computer system if given the power, the system has functioned only in the inactive state, when in analogikan to humans in a state of sleep, which the system will be ready whenever given the command to activate all systems. That's because when the phone has the battery then plug in battery voltage will go straight to the IC power supply, while at the same power supply IC will provide voltage to the processor. SW circuit On / Off cell phone you can see in the image of this diawah.


3.3.1 Distribution voltage

Circuits in cell phones there are many subsystems, which each sub-system has a voltage supply needs of different and at each voltage when the system will be given when necessary. Power given by the first mobile phone battery, the voltage from battrey will continue to power supply IC, the IC power supply voltage supplylah all will be provided depending on needs.

3.3.1 Battery Charging

Mobile phone battery charging process is very thorough at all, whereby the charging system will be computerized. Battery voltage will be in diteksi by the IC power supply and CPU, if the battery in a full state of the phone will reject the filling of the transformer charger. This charging system is processed by charging IC.

3.4 Transmission of information data


Basically, a transmission system in communication systems, there are two systems, the reception (receiver) that serves as reception of data or voice information, alphanumeric data and graphics from the base station to the mobile phone. While the transmitting (Tx) functions as a voice or data transmission information, alphanumeric data, graphics and network registration process

3.4.1 The registration process network


3.4.1.1 Initialization


The first time you make phone calls called by the initialization process. This occurs when you first activate your phone. You'll get a connection from the site terdekekat sell, then the cellular network will perform checks your account or membership is still active or not, then your calls will be processed further.

3.4.1.2 Inspection frequency list


Your phone will check the list of frequencies on your SIM. Inspection covers carrie frequency flow quality, then look for Broadcash Control Channel or BCCH. Each BCCH will transmit a unique data markers, membedan between AMPS and GSM. In the AMPS system uses a dedicated radio frequency system in each cell, whereas on all GSM frequencies can carry information, but more important is the channel used to stream data rather than radio frequency

3.4.1.3 Identification of information


Base station or Broadcash Control Center will continue to deliver for the identification of information about the sell the site. The identity of the wireless network is Carreier itself, then the area code location, and frequency yag used, as well as information about the surrounding cells. All information is used to determine whether your phone is active and in need of service. BCCH is not a radio frequency didedicated. BBCH will use the channel that will carry information in the form of bits at all frequencies within a cell.

3.4.1.4 Control Channel Control Inspection Broadcash


Cell phone radio frequencies will conduct examination bradcash control channel, where your phone will send a signal to review whether the signals are still within range. The phone will be like a radio scanning the entire list of BCCH frequencies one by one and check the signal reception. Measurements will be conducted at each level of the channel. Cell site will send a strong signal to your phone. Meanwhile in broadcash control channel is a mobile data stream from the monitor did ase station called frequency control or frequency control channel burs burs (FCCB). Your mobile phone signals will synchronize with the system provider with wireless connection means. Once your phone has been communicating with the base station, then everything is ready for use.

3.4.2. Transmitting information data


3.4.2.1. signal processing of voice data, graphics, alphanumeric.

While mobile phone users are communicating, then the sound wave signal generated by mobile users will travel through the air. Gelobang voice signal will be received by the microphone to be converted into electromagnetic waves. And will proceed to the audio processor to be strengthened and processed.

If mobile phone users to sms, then type the command on the keyboard by mobile phone users will be processed by the CPU (Central Proccesor Unit)

3.4.2.2. changes in the digital signal into an analog signal (D / A converter).


In this section the data signal information is converted into an analog signal form. Because the RF section is still using an analog signal is shaped in part while the main processor in the form of a digital character. This needs to be an adjustment between two different characters that can be interconnected.

Furthermore, the data signal information already in will continue to convert the RF section.

3.4.2.3. Mixing the data signal with the carrier signal.


Information data signal will be sent to the base station, surely there must be a data signal carrying the information. Therefore, the information data signal will be mixed with the carrier by the RF signal processor. Carrier signal on GSM technology has a 900-1900 MHz frequency range, these waves are initially generated by the VCO, where the VCO will generate a wave of 3420-3840 MHz, which would then be in if the RF processor.

After the data signal information mixed with a carrier signal will then proceed to the section is called the modulation penguatan.sistem.

3.4.2.4. Strengthening end


Signal data information that has been mixed with the carrier signal will be received by the base station, while the distance to the mobile phone base stations far enough. Then the signal has to be really strong to be received by the base station. Then the signal must be reinforced by the PA Power Amplyfier. When strengthening the end of the delivery is not functioning properly then the phone will not be able to register network to the operator, this is caused because the base station can not receive the data signal information from mobile phones.

3.4.2.5. Distribution of Transmission lines


Once confirmed then the signal will be continued to the antenna switch for connecting to the antenna. Antenna switches can be in analogikan like airports, where in the data transmission of information in cell phones, there are two pathways, namely receiving and transmitting. So without the antenna switch on the received signal with the signal to be emitted will collide with each other, because there is only on GSM technology, there is one lane with a system called TDMA.

3.4.2.6. Transmitting to the base station


The next signal will be emitted through the antenna to the base station. Antenna will determine the outcome of the broadcast, then the signal is weak or strong depending on the quality antennanya.

3.4.3. Receipt of information data.


3.4.3.1. Receiving data from the base station


Signal emitted by the base station information to be received in advance by phone antennas. And then be forwarded on to the antenna switch for forwarded to the LNA.

3.4.3.2. Distribution of transmission lines


In order for transmitting signals do not collide with the signal reception, it will be first divided transmission signal by the antenna switch.


3.4.3.3. Strengthening early


So that the signal can be received well by the RF signals emitted by base stations will be strengthened first by the LNA (Low Noise Amplyfier). LNA not only functioned as a reinforcement, but can enable the cutting noise (sigh).


3.4.3.4. Separation of the carrier signal with the signal information


Signals generated by the LNA still mixed with a carrier signal, in order to be processed by the DSP (Digital Signal proccersor) then the data signal information must be separated first by the RF processor. This system is called the frequency.


3.4.3.5. changes in the analog signal into digital signal (D / A converter).


In this section the data signal information is converted into digital signal form. Because the RF section is still using an analog signal is shaped in part while the main processor in the form of a digital character. This needs to be an adjustment between two different characters that can be interconnected.

Furthermore, the data signal information already in the convert will be continued to the main processor (CPU). When the data signal is a voice tersubut information will be continued to the audio amplifier.


3.4.3.6. Strengthening the end of the voice signal


When the data signal information is voice data, it will be reinforced by an audio amplifier terlabih first before continuing to the speakers. Audio signal will be converted into electromagnetic waves, then needs to connect to the speakers so that the electromagnetic signals into sound signals which propagate in the air to be heard by people ears.

 

[josher]

How to Work HandPhone

1.3 Introduction

Before you go any further about repairing mobile phones, of course, you must first understand the working principle of mobile phones in order to simplify the process of analysis of damage to the phone.

In this chapter will be discussed in broad outline and in general, because the development of mobile technology today is always changing.

Center 2.3 command processing input / output.


3.2.1 Command input.


Each time you make an order to the phone, for example typing an sms, play games, changing phone settings, voice recording, photos, and others. All of the above command is a command from the mobile phone users, which can pass the command-like device: keypad, camera, infra red, Bluetooth. All input commands will be accepted by the CPU, then the CPU will process all the input commands. CPU can process all the input commands based on system operating data contained in the IC flash. IC flash will store the input data when commanded by the CPU, RAM, while the IC will accept data from the CPU for a while.

3.2.1 Command Output.

CPU will provide overall command of the command input, the command from the CPU is very universal in the overall mobile phone navigation system, for example: giving the order to display graphical information on the LCD, giving orders to the UI (vibrator, buzzer, LED), gives orders to the power supply voltage to meretribusikan , and others.

3.3 Power Supply


3.3.1 Power up / down (On / Off)


The process to turn the phone is not the same as ordinary electronic circuits such as radio, etc. TV. At almost the same phone system with a computer, where the process does not turn on or turn off by disconnect power to the power supply. In the actual computer system if given the power, the system has functioned only in the inactive state, when in analogikan to humans in a state of sleep, which the system will be ready whenever given the command to activate all systems. That's because when the phone has the battery then plug in battery voltage will go straight to the IC power supply, while at the same power supply IC will provide voltage to the processor. SW circuit On / Off cell phone you can see in the image of this diawah.


3.3.1 Distribution voltage

Circuits in cell phones there are many subsystems, which each sub-system has a voltage supply needs of different and at each voltage when the system will be given when necessary. Power given by the first mobile phone battery, the voltage from battrey will continue to power supply IC, the IC power supply voltage supplylah all will be provided depending on needs.

3.3.1 Battery Charging

Mobile phone battery charging process is very thorough at all, whereby the charging system will be computerized. Battery voltage will be in diteksi by the IC power supply and CPU, if the battery in a full state of the phone will reject the filling of the transformer charger. This charging system is processed by charging IC.

3.4 Transmission of information data


Basically, a transmission system in communication systems, there are two systems, the reception (receiver) that serves as reception of data or voice information, alphanumeric data and graphics from the base station to the mobile phone. While the transmitting (Tx) functions as a voice or data transmission information, alphanumeric data, graphics and network registration process

3.4.1 The registration process network


3.4.1.1 Initialization


The first time you make phone calls called by the initialization process. This occurs when you first activate your phone. You'll get a connection from the site terdekekat sell, then the cellular network will perform checks your account or membership is still active or not, then your calls will be processed further.

3.4.1.2 Inspection frequency list


Your phone will check the list of frequencies on your SIM. Inspection covers carrie frequency flow quality, then look for Broadcash Control Channel or BCCH. Each BCCH will transmit a unique data markers, membedan between AMPS and GSM. In the AMPS system uses a dedicated radio frequency system in each cell, whereas on all GSM frequencies can carry information, but more important is the channel used to stream data rather than radio frequency

3.4.1.3 Identification of information


Base station or Broadcash Control Center will continue to deliver for the identification of information about the sell the site. The identity of the wireless network is Carreier itself, then the area code location, and frequency yag used, as well as information about the surrounding cells. All information is used to determine whether your phone is active and in need of service. BCCH is not a radio frequency didedicated. BBCH will use the channel that will carry information in the form of bits at all frequencies within a cell.

3.4.1.4 Control Channel Control Inspection Broadcash


Cell phone radio frequencies will conduct examination bradcash control channel, where your phone will send a signal to review whether the signals are still within range. The phone will be like a radio scanning the entire list of BCCH frequencies one by one and check the signal reception. Measurements will be conducted at each level of the channel. Cell site will send a strong signal to your phone. Meanwhile in broadcash control channel is a mobile data stream from the monitor did ase station called frequency control or frequency control channel burs burs (FCCB). Your mobile phone signals will synchronize with the system provider with wireless connection means. Once your phone has been communicating with the base station, then everything is ready for use.

3.4.2. Transmitting information data


3.4.2.1. signal processing of voice data, graphics, alphanumeric.

While mobile phone users are communicating, then the sound wave signal generated by mobile users will travel through the air. Gelobang voice signal will be received by the microphone to be converted into electromagnetic waves. And will proceed to the audio processor to be strengthened and processed.

If mobile phone users to sms, then type the command on the keyboard by mobile phone users will be processed by the CPU (Central Proccesor Unit)

3.4.2.2. changes in the digital signal into an analog signal (D / A converter).


In this section the data signal information is converted into an analog signal form. Because the RF section is still using an analog signal is shaped in part while the main processor in the form of a digital character. This needs to be an adjustment between two different characters that can be interconnected.

Furthermore, the data signal information already in will continue to convert the RF section.

3.4.2.3. Mixing the data signal with the carrier signal.


Information data signal will be sent to the base station, surely there must be a data signal carrying the information. Therefore, the information data signal will be mixed with the carrier by the RF signal processor. Carrier signal on GSM technology has a 900-1900 MHz frequency range, these waves are initially generated by the VCO, where the VCO will generate a wave of 3420-3840 MHz, which would then be in if the RF processor.

After the data signal information mixed with a carrier signal will then proceed to the section is called the modulation penguatan.sistem.

3.4.2.4. Strengthening end


Signal data information that has been mixed with the carrier signal will be received by the base station, while the distance to the mobile phone base stations far enough. Then the signal has to be really strong to be received by the base station. Then the signal must be reinforced by the PA Power Amplyfier. When strengthening the end of the delivery is not functioning properly then the phone will not be able to register network to the operator, this is caused because the base station can not receive the data signal information from mobile phones.

3.4.2.5. Distribution of Transmission lines


Once confirmed then the signal will be continued to the antenna switch for connecting to the antenna. Antenna switches can be in analogikan like airports, where in the data transmission of information in cell phones, there are two pathways, namely receiving and transmitting. So without the antenna switch on the received signal with the signal to be emitted will collide with each other, because there is only on GSM technology, there is one lane with a system called TDMA.

3.4.2.6. Transmitting to the base station


The next signal will be emitted through the antenna to the base station. Antenna will determine the outcome of the broadcast, then the signal is weak or strong depending on the quality antennanya.

3.4.3. Receipt of information data.


3.4.3.1. Receiving data from the base station


Signal emitted by the base station information to be received in advance by phone antennas. And then be forwarded on to the antenna switch for forwarded to the LNA.

3.4.3.2. Distribution of transmission lines


In order for transmitting signals do not collide with the signal reception, it will be first divided transmission signal by the antenna switch.


3.4.3.3. Strengthening early


So that the signal can be received well by the RF signals emitted by base stations will be strengthened first by the LNA (Low Noise Amplyfier). LNA not only functioned as a reinforcement, but can enable the cutting noise (sigh).


3.4.3.4. Separation of the carrier signal with the signal information


Signals generated by the LNA still mixed with a carrier signal, in order to be processed by the DSP (Digital Signal proccersor) then the data signal information must be separated first by the RF processor. This system is called the frequency.


3.4.3.5. changes in the analog signal into digital signal (D / A converter).


In this section the data signal information is converted into digital signal form. Because the RF section is still using an analog signal is shaped in part while the main processor in the form of a digital character. This needs to be an adjustment between two different characters that can be interconnected.

Furthermore, the data signal information already in the convert will be continued to the main processor (CPU). When the data signal is a voice tersubut information will be continued to the audio amplifier.


3.4.3.6. Strengthening the end of the voice signal


When the data signal information is voice data, it will be reinforced by an audio amplifier terlabih first before continuing to the speakers. Audio signal will be converted into electromagnetic waves, then needs to connect to the speakers so that the electromagnetic signals into sound signals which propagate in the air to be heard by people ears.

 

[josher]

Cellphone Basics

EXPLANATION OF THE BASIC THEORY OF OPERATION OF A MOBILE PHONE IN A VERY SIMPLE WAY:​

HAVE YOU EXPERIENCED THE FACT THAT IN A MUSIC LISTENED FROM A VERY LONG DISTANCE, THE SOUNDS OF DRUMS ARE LESS AUDIBLE THAN THE SOUNDS OF OTHER SHARP INSTRUMENTS LIKE GUITAR ? YES THIS IS BECAUSE THE SOUND OF A DRUM IS A LOW FREQUENCY SIGNAL AND LOW FREQUENCIES CANNOT TRAVEL LONG DISTANCES EASILY WHILE THE HIGH FREQUENCIES LIKE THE SOUND OF GUITAR OR OTHER STRING INSTRUMENTS CAN ! SEE HOW THIS IS APPLIED IN THE RADIO, TV AND MOBILE TECHNOLOGY FOR YOURSELF. AFTER ALL THE MOBILE PHONE IS ALSO A RADIO TELEPHONE ! THE BROAD MEANING OF THE WORD "RADIO" IS WIRELESS. THE PRINCIPLE OF A MOBILE PHONE CAN BE COMPARED WITH THAT OF A RADIO OR A TELEVISION SYSTEM.

There are two parts in mobile phone 1. is Transmiting & 2. is Receiving

TRANSMITTING PART..

THE VOICE SIGNAL WHICH IS BASICALLY IN THE FREQUENCY RANGE OF 15 HERTZ TO ABOUT 20 KILOHERTZ (1KILOHERTZ=1000 HERTZ)AND IS IN THE LOWEST FREQ.BAND IN THE NORMAL FREQUENCY SPECTRUM, WHICH IS REQUIRED TO BE SENT TO THE OTHER MOBILE PHONE IS FIRST CONVERTED FROM ANALOG TO DIGITAL TYPE OF SIGNAL AND IS THEN MIXED WITH A VERY HIGH FREQUENCY SIGNAL IN THE RANGE OF HUNDREDS OF MEGAHERTZ (1 MEGAHERTZ = 1000KILOHERTZ=1000X1000 HERTZ=1000000 HERTZ) IN THE MOBILE PHONE , THIS IS CALLED MODULATION, WHICH MEANS CHANGING THE AUDIO SIGNAL BY ADDING ANOTHER VERY HIGH FREQUENCY TO IT , THE HIGH FREQUENCY BEING USED AS CARRIER FREQUENCY TO CARRY THE VOICE OR THE AUDIO SIGNAL. THIS IS DONE TO MAKE IT POSSIBLE TO BE SENT THRO' AIR TO THE NEAREST TOWER OF THE SERVICE OPERATOR. THE BASIC PRINCIPLE BEING THAT THE HIGH FREQUENCIES CAN TRAVEL LONGER DISTANCES EASILY.

RECEIVING PART

IN THE RECEIVING PART, THE REVERSE (DE-MODULATION) IS REQUIRED TO BE DONE. THE RECEIVED SIGNAL FROM THE SERVICE OPERATOR'S TOWER IS REQUIRED TO BE DEMODULATED TO REMOVE THE HIGH FREQUENCY SIGNAL OR THE CARRIER FREQUENCY SIGNAL FROM THE RECEIVED SIGNAL, SO THAT ONLY DIGITAL AUDIO SIGNAL IS LEFT OUT. IN MOBILE PHONES, THIS DIGITAL AUDIO SIGNAL IS THEN CONVERTED TO ANALOG SIGNAL AND AFTER SOME AMPLIFICATION ETC. IS SENT TO THE SPEAKER TO BE HEARD BY THE USER.

BOTH THIS TRANSMITTING (TX) AND RECEIVING (RX) FUNCTIONS ARE REQUIRED TO BE CARRIED OUT IN THE MOBILE PHONE ITSELF AND IS DONE BY WHAT CAN BE CALLED THE RF SECTION OF THE MOBILE.

What is Frequency ?

What is frequency? and what are mobile frequencies?

Mobile phone uses radio waves to communicate with other mobile phones and when you are face to face with radio waves you have to learn about frequencies.

The word frequency is derived from the word frequently which is used with the meaning of circulation of any task repeated with same time period. so if any task is repeated with a same time period you can call its ratio as frequency. In radio waves a the speed of waves going up and down is called frequency and it is measured in Hz(Hertz). if a wave finishes its ten cycles in a second its frequency will be 10 Hz. look at the chart below to learn more about the frequencies.

1 cycle/second = 1Hz

1000 Hz =1Kilo Hertz (1Khz)

1000Khz =1 Mega Hertz (1Mhz)

1000Mhz =1 Giga Hertz (1Ghz)

1000Ghz = 1 Tera hertz (1Thz)

​

Cell Technology

Geographic areas are divided into a number of slightly overlapping circular "cells." Each cell contains a base station, which is identifiable by its transmitting and receiving antenna located on a tower at the top of a hill or building. The base stations connect to the landline telephone system of the country. The multiple cells combined with low power transmitters allow the same frequencies to be reused with different conversations in different cells within the same city or locale. The primary digital cellphone technologies are TDMA, CDMA and GSM. see cellsite.

​

Lets see the first GSM mobile phone how it looks like!
First Cellphone in U.S. Introduced in 1983, this Motorola DynaTAC cost $3,995 and weighed two pounds. (Image courtesy of Motorola, Inc.)

​

Mobile phone features

Main article: Mobile phone features Mobile phones often have features beyond sending text messages and making voice callsââ‚ƚ¬Ã¢â‚¬ÂÂÂ�including Internet browsing, music (MP3) playback, personal organizers, e-mail, built-in cameras and camcorders, ringtones, games, radio, Push-to-Talk (PTT), infrared and Bluetooth connectivity, call registers, ability to watch streaming video or download video for later viewing, and serving as a wireless modem for a PC.

Technology

Mobile phone tower Mobile phones and the network they operate under vary significantly from provider to provider, and even from nation to nation. However, all of them communicate through electromagnetic radio waves with a cell site base station, the antennas of which are usually mounted on a tower, pole, or building. The phones have a low-power transceiver that transmits voice and data to the nearest cell sites, usually .5 to 8 miles (0.8 to 13 kilometres) away. When the cellular phone or data device is turned on, it registers with the mobile telephone exchange, or switch, with its unique identifiers, and will then be alerted by the mobile switch when there is an incoming telephone call. The handset constantly listens for the strongest signal being received from the surrounding base stations. As the user moves around the network, the mobile device will "handoff" to various cell sites during calls, or while waiting (idle) between calls it will reselect cell sites. Cell sites have relatively low-power (often only one or two watts) radio transmitters which broadcast their presence and relay communications between the mobile handsets and the switch. The switch in turn connects the call to another subscriber of the same wireless service provider or to the public telephone network, which includes the networks of other wireless carriers. The dialogue between the handset and the cell site is a stream of digital data that includes digitized audio (except for the first generation analog networks). The technology that achieves this depends on the system which the mobile phone operator has adopted. Some technologies include AMPS for analog, and TDMA, CDMA, GSM, GPRS, EV-DO, and UMTS for digital communications. Each network operator has a unique radio frequency band. ​

 

[josher]

Cellphone Basics

EXPLANATION OF THE BASIC THEORY OF OPERATION OF A MOBILE PHONE IN A VERY SIMPLE WAY:​

HAVE YOU EXPERIENCED THE FACT THAT IN A MUSIC LISTENED FROM A VERY LONG DISTANCE, THE SOUNDS OF DRUMS ARE LESS AUDIBLE THAN THE SOUNDS OF OTHER SHARP INSTRUMENTS LIKE GUITAR ? YES THIS IS BECAUSE THE SOUND OF A DRUM IS A LOW FREQUENCY SIGNAL AND LOW FREQUENCIES CANNOT TRAVEL LONG DISTANCES EASILY WHILE THE HIGH FREQUENCIES LIKE THE SOUND OF GUITAR OR OTHER STRING INSTRUMENTS CAN ! SEE HOW THIS IS APPLIED IN THE RADIO, TV AND MOBILE TECHNOLOGY FOR YOURSELF. AFTER ALL THE MOBILE PHONE IS ALSO A RADIO TELEPHONE ! THE BROAD MEANING OF THE WORD "RADIO" IS WIRELESS. THE PRINCIPLE OF A MOBILE PHONE CAN BE COMPARED WITH THAT OF A RADIO OR A TELEVISION SYSTEM.

There are two parts in mobile phone 1. is Transmiting & 2. is Receiving

TRANSMITTING PART..

THE VOICE SIGNAL WHICH IS BASICALLY IN THE FREQUENCY RANGE OF 15 HERTZ TO ABOUT 20 KILOHERTZ (1KILOHERTZ=1000 HERTZ)AND IS IN THE LOWEST FREQ.BAND IN THE NORMAL FREQUENCY SPECTRUM, WHICH IS REQUIRED TO BE SENT TO THE OTHER MOBILE PHONE IS FIRST CONVERTED FROM ANALOG TO DIGITAL TYPE OF SIGNAL AND IS THEN MIXED WITH A VERY HIGH FREQUENCY SIGNAL IN THE RANGE OF HUNDREDS OF MEGAHERTZ (1 MEGAHERTZ = 1000KILOHERTZ=1000X1000 HERTZ=1000000 HERTZ) IN THE MOBILE PHONE , THIS IS CALLED MODULATION, WHICH MEANS CHANGING THE AUDIO SIGNAL BY ADDING ANOTHER VERY HIGH FREQUENCY TO IT , THE HIGH FREQUENCY BEING USED AS CARRIER FREQUENCY TO CARRY THE VOICE OR THE AUDIO SIGNAL. THIS IS DONE TO MAKE IT POSSIBLE TO BE SENT THRO' AIR TO THE NEAREST TOWER OF THE SERVICE OPERATOR. THE BASIC PRINCIPLE BEING THAT THE HIGH FREQUENCIES CAN TRAVEL LONGER DISTANCES EASILY.

RECEIVING PART

IN THE RECEIVING PART, THE REVERSE (DE-MODULATION) IS REQUIRED TO BE DONE. THE RECEIVED SIGNAL FROM THE SERVICE OPERATOR'S TOWER IS REQUIRED TO BE DEMODULATED TO REMOVE THE HIGH FREQUENCY SIGNAL OR THE CARRIER FREQUENCY SIGNAL FROM THE RECEIVED SIGNAL, SO THAT ONLY DIGITAL AUDIO SIGNAL IS LEFT OUT. IN MOBILE PHONES, THIS DIGITAL AUDIO SIGNAL IS THEN CONVERTED TO ANALOG SIGNAL AND AFTER SOME AMPLIFICATION ETC. IS SENT TO THE SPEAKER TO BE HEARD BY THE USER.

BOTH THIS TRANSMITTING (TX) AND RECEIVING (RX) FUNCTIONS ARE REQUIRED TO BE CARRIED OUT IN THE MOBILE PHONE ITSELF AND IS DONE BY WHAT CAN BE CALLED THE RF SECTION OF THE MOBILE.

What is Frequency ?

What is frequency? and what are mobile frequencies?

Mobile phone uses radio waves to communicate with other mobile phones and when you are face to face with radio waves you have to learn about frequencies.

The word frequency is derived from the word frequently which is used with the meaning of circulation of any task repeated with same time period. so if any task is repeated with a same time period you can call its ratio as frequency. In radio waves a the speed of waves going up and down is called frequency and it is measured in Hz(Hertz). if a wave finishes its ten cycles in a second its frequency will be 10 Hz. look at the chart below to learn more about the frequencies.

1 cycle/second = 1Hz

1000 Hz =1Kilo Hertz (1Khz)

1000Khz =1 Mega Hertz (1Mhz)

1000Mhz =1 Giga Hertz (1Ghz)

1000Ghz = 1 Tera hertz (1Thz)

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Cell Technology

Geographic areas are divided into a number of slightly overlapping circular "cells." Each cell contains a base station, which is identifiable by its transmitting and receiving antenna located on a tower at the top of a hill or building. The base stations connect to the landline telephone system of the country. The multiple cells combined with low power transmitters allow the same frequencies to be reused with different conversations in different cells within the same city or locale. The primary digital cellphone technologies are TDMA, CDMA and GSM. see cellsite.

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Lets see the first GSM mobile phone how it looks like!
First Cellphone in U.S. Introduced in 1983, this Motorola DynaTAC cost $3,995 and weighed two pounds. (Image courtesy of Motorola, Inc.)

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Mobile phone features

Main article: Mobile phone features Mobile phones often have features beyond sending text messages and making voice callsââ‚ƚ¬Ã¢â‚¬ÂÂÂ�including Internet browsing, music (MP3) playback, personal organizers, e-mail, built-in cameras and camcorders, ringtones, games, radio, Push-to-Talk (PTT), infrared and Bluetooth connectivity, call registers, ability to watch streaming video or download video for later viewing, and serving as a wireless modem for a PC.

Technology

Mobile phone tower Mobile phones and the network they operate under vary significantly from provider to provider, and even from nation to nation. However, all of them communicate through electromagnetic radio waves with a cell site base station, the antennas of which are usually mounted on a tower, pole, or building. The phones have a low-power transceiver that transmits voice and data to the nearest cell sites, usually .5 to 8 miles (0.8 to 13 kilometres) away. When the cellular phone or data device is turned on, it registers with the mobile telephone exchange, or switch, with its unique identifiers, and will then be alerted by the mobile switch when there is an incoming telephone call. The handset constantly listens for the strongest signal being received from the surrounding base stations. As the user moves around the network, the mobile device will "handoff" to various cell sites during calls, or while waiting (idle) between calls it will reselect cell sites. Cell sites have relatively low-power (often only one or two watts) radio transmitters which broadcast their presence and relay communications between the mobile handsets and the switch. The switch in turn connects the call to another subscriber of the same wireless service provider or to the public telephone network, which includes the networks of other wireless carriers. The dialogue between the handset and the cell site is a stream of digital data that includes digitized audio (except for the first generation analog networks). The technology that achieves this depends on the system which the mobile phone operator has adopted. Some technologies include AMPS for analog, and TDMA, CDMA, GSM, GPRS, EV-DO, and UMTS for digital communications. Each network operator has a unique radio frequency band. ​