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Basic Knowledge of GSM Mobile Phones

By Philip Perez,2018-03-01 22:53:00
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Basic Knowledge of GSM Mobile Phones

The ordinary GSM mobile phone is composed of two parts: software and hardware. The software is the working program of the mobile phone. The circuit of each part of the control hardware works in a certain mode. The hardware includes: the power supply part, the logic audio part, the radio frequency part and the clock part.

I. POWER SUPPLY SECTION:

1. Composition: Mobile phone power circuit is divided into two categories: logic voltage and RF voltage.

Logical voltage:1.8V or 2.8V constant voltage.

RF voltage:2.8V jump voltage.

2.role: the power supply part of the main 3.6V battery voltage, according to different requirements of the circuit to provide the required operating voltage.

II. The logical audio component:

1.Composition:

Mobile phone logic circuit is divided into audio processing circuit and logic control circuit (including man-machine interface circuit).

Audio circuit is divided into: receive circuit, send circuit, headset (Bluetooth headset) send and receive circuit.

Logic control circuit (man-machine interface circuit) is divided into: keyboard scanning circuit, display circuit, ringing circuit, vibration circuit, backlight circuit, SIM card, camera circuit, MP3 / MP4 circuit.

2. Role:

a) The role of the logical component:

The logic part is the command and control center of all the components of the mobile phone; all the data processing and function circuits of receiving and transmitting are controlled by it.

b) The role of the audio component:

When transmitting, the sound is converted into an electric current signal and a four-way transmitting baseband signal is formed.

When receiving, the receiving baseband signal is reduced to analog audio in the audio, and after amplifying, the receiver is driven to make sound.

III. RF component:

1.Composition:

The radio frequency circuit of mobile phone is composed of: receiving circuit, transmitting circuit, native oscillation circuit (this electromechanical circuit, frequency synthesis circuit, frequency combination circuit, phase-locked loop circuit) and so on.

2. Role:

a) receiving circuit: the base station to send electromagnetic waves into weak AC current signal demodulation, receive baseband signal.

b) transmitting circuit: the transmitting baseband information modulated into the transmitting frequency signal; amplifier amplifier by the antenna to electromagnetic radiation out.

c) local oscillation circuit: generate four segments without any information of the local frequency signal, the receiving signal demodulation and phase modulation of the transmitting band information.

IV. Clock section:

1. composition: GSM mobile phones in the clock are:32.768 KHZ and 13MHZ two.

2. Role:

a) 32.768 KHZ clock:

Provides a time display and changes to a running clock when the phone is on standby.

b) 13MHZ clock:

1) to the CPU to run the clock (tube boot) ;

2) send the local circuit as a frequency reference (tube signal).

V. Flowchart of mobile phone composition:

MobileMobile

Mobile

Mobile

HardwareHardwaresoftwaresoftware

Hardware

Hardware

software

software

Logic powerLogic power

Logic power

Logic power

13M Clock Circuit13M Clock Circuit

13M Clock Circuit

13M Clock Circuit

Audio CircuitsAudio CircuitsNativeVibration CircuitNativeVibration CircuitReceiving CircuitReceiving CircuitTransmit CircuitTransmit CircuitLogic CircuitsLogic Circuits

Audio Circuits

Audio Circuits

NativeVibration Circuit

NativeVibration Circuit

Receiving Circuit

Receiving Circuit

Transmit Circuit

Transmit Circuit

Logic Circuits

Logic Circuits

Headphone CircuitHeadphone CircuitTransmission circuitTransmission circuitReceiver CircuitsReceiver Circuits

Headphone Circuit

Headphone Circuit

Transmission circuit

Transmission circuit

Receiver Circuits

Receiver Circuits

SIMcard circuSIMcard circuVibrationCircuitsVibrationCircuitsRing CircuitRing CircuitBacklight CircuitBacklight CircuitMP3 / 4 Circuit Memory Card CircuitMP3 / 4 Circuit Memory Card CircuitCamera Circuit Keyboard ScanCamera Circuit Keyboard ScanDisplay Circuit Backlight CircuitDisplay Circuit Backlight CircuitRingCircuit Vibration CircuitRingCircuit Vibration CircuitDisplay CircuitsDisplay CircuitsRF PowerRF PowerPowerPowerLogic CircuitsLogic CircuitsRF CircuitsRF Circuits

SIMcard circu

SIMcard circu

VibrationCircuits

VibrationCircuits

Ring Circuit

Ring Circuit

Backlight Circuit

Backlight Circuit

MP3 / 4 Circuit Memory Card Circuit

MP3 / 4 Circuit Memory Card Circuit

Camera Circuit Keyboard Scan

Camera Circuit Keyboard Scan

Display Circuit Backlight Circuit

Display Circuit Backlight Circuit

RingCircuit Vibration Circuit

RingCircuit Vibration Circuit

Display Circuits

Display Circuits

RF Power

RF Power

Power

Power

Logic Circuits

Logic Circuits

RF Circuits

RF Circuits

Sixth, the mobile phone block diagram:

CPU(Audio)CPU(Audio)Receive DemodulationReceive DemodulationAntenna SwitchAntenna Switch900M

CPU

(Audio)

CPU

(Audio)

Receive Demodulation

Receive Demodulation

Antenna Switch

Antenna Switch

1800M

Frequency rate combinationFrequency rate combination

Frequency rate combination

Frequency rate combination

TransmitterTransmitterVCCFrequency sampling

Transmitter

Transmitter

Frequency DivisionFrequency DivisionR XVCOOR XVCOO13M

Frequency Division

Frequency Division

R X

VCOO

R X

VCOO

CLK

DAT

RST

Power Sampling Signal

TXVCOTXVCOTransmit Frequency Sampling

TX

VCO

TX

VCO

ModulationModulationPhase IdentificationPhase IdentificationPower AmplifierPower Amplifier

Modulation

Modulation

Phase Identification

Phase Identification

Power Amplifier

Power Amplifier

Power ControlPower Control

Power Control

Power Control

Grade RF VoltageLogic Voltage

Power Integration BlockPower Integration Block

Power Integration Block

Power Integration Block

(Mobile phone block diagram)

Seven, mobile phone components arrangement diagram:

Antenna SwitchAntenna SwitchAmplifierAmplifierFeature On PhoneLeft Rightdown Call Clear Power On1 2 34 5 67 8 9* 0 #Feature On PhoneLeft Rightdown Call Clear Power On1 2 34 5 67 8 9* 0 # Filters FiltersDisplayDisplay

Antenna Switch

Antenna Switch

Amplifier

Amplifier

Feature On Phone

Left Right

down

Call Clear Power On

1 2 3

4 5 6

7 8 9

* 0 #

Feature On Phone

Left Right

down

Call Clear Power On

1 2 3

4 5 6

7 8 9

* 0 #

Filters

Filters

Display

Display

PowerControlPowerControlTail PlugTail Plug

PowerControl

PowerControl

Tail Plug

Tail Plug

Intermediate FrequencyIntermediate FrequencyVCOVCO

Intermediate Frequency

Intermediate Frequency

VCO

VCO

13M13MVCOVCO

13M

13M

VCO

VCO

Power SupplyPower Supply

Power Supply

Power Supply

CPUCPU

CPU

CPU

FontLibraryFontLibrary

FontLibrary

FontLibrary

Card HolderCard HolderStagingStaging

Card Holder

Card Holder

Staging

Staging

Tail PlugTail Plug

Tail Plug

Tail Plug

(Mobile phone components arrangement diagram)

Identification of mobile phone components:

1, the machine board is a multilayer fiber splint, a total of four layers of circuit; the front for the keyboard board; the back for the logic board; the middle layer for the hole line; the other layer for the common ground.

2, the board is generally divided into three parts, separated by a yellow public; the top part of the launch; the middle part of the receiving and local vibration; the lower part of the logical audio.

3, the antenna switch at the top of the board near the antenna contact; next to the power amplifier and power control (hybrid machine antenna switch and power amplifier integration, more some mobile phones do not have power control).

4, high-frequency filter in the antenna switch and the intermediate frequency, for the white gold or white cube.

5, in the middle of the board, next to the 13M or 26M crystal, high-frequency filters and VCO, a lot of small capacitors (or white tantalum capacitors).

6, RX-VCO next to the IF, white body with shield.

7, TX-VCO between the intermediate frequency and the power amplifier, the volume is larger than RX-VCO.

8, CPU, font library, temporary existence of the lower end of the machine board, most of the plastic, next to few peripheral components; the general size of the CPU, font library, temporary storage rectangular.

9, the power supply in the lower end of the chassis, close to the SIM card seat; next to a lot of larger capacitors (most will have an electrolytic capacitor and the battery positive pole in parallel).

10, the current majority of mobile phones do not have independent audio, are integrated in the power supply or CPU.