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wirefree 06-01-2009 08:50

Nokia 1100 circuitboard query
Requesting assistance from all hardware experts with identifying the components marked '???' on a Nokia 1100 circuit board, the image for which is available at the following URL:

Would greatly appreciate a prompt response.

Best regards,

aliarjun 06-01-2009 09:12

Image could not open. please attach it again.

marekom 06-01-2009 09:33

Here is bro

wirefree 06-03-2009 22:54

Any assistance regarding the above query would be greatly appreciated.


aliarjun 06-08-2009 14:32

1 Attachment(s)
Attachment 200783

hope this image can help you

wirefree 06-12-2009 03:00

Greatly appreciate that, aliarjun. Your detailed response has proven extremely informative. It has further encouraged me to delve into the RF components of the circuitry and better understand them.

As a follow-up, could I request you to attempt to address each of the following listed components individually & collectively - what they do, what their role is in transmitting/receiving signals, and at what stage in the Tx/Rx process are they required.

- Diode Rectifier: Used for detection of radio signals???
- Antenna Switch: Used for switching between 900/1800 MHz frequency bands???
- RF Amplifier: Used for amplification of low-power frequency to a high-power 900/1800 MHz frequencies???
- RF IC: Used for processing RF. Could I get you to explain what precisely does processing of RF entail and why is it required?
- Voltage-Controlled Oscillator (VCO): Used for oscillating human analog voice signals into digital signals???
- Crystal (Quartz): Used simply for producing frequency signals. (Would you know its internals?)

Look forward to your prompt response.

Best regards,

Ashwani Gaur 06-12-2009 05:50

well, as i can see in this pic

there are some corrections as below:-

1. Diode Rectifier:- its is not a DIODE, its CAPACITOR used to clean any noise in DC , also helps to stabilize DC voltage

2. Ant Switch:- it works two way, one for switiching of ant between RX AND TX section of mobile phone as well as switching of mobile bands ie 900/1800 as per sim card used in the phone

3. RF Amplifier:- to communicate betwenn you and nearest mobile tower, you need to have some power in your TX signal, so that it can reach nearest tower , in GSM 900 Mhz, upto 2W of rf power can be produced by this RF-AMPLIFIER

RF IC:- signal received by mobile phone is a complex signal, rf-ic , process this signal to demodulate so that intelligence in the signal can be extracted like VOICE OR SMS.
This rf-ic converts received signal into digital signal which is further proccessed by D2A converter to get audio from received rf signal

Voltage-Controlled Oscillator (VCO):- Used for oscillating human analog voice signals into digital signals???

this is totally wrong info
correct one is here:-
Voltage-Controlled Oscillator (VCO):- its a kind of electronic tuner, it tunes and locks to the correct channel used in any specific band

Crystal (Quartz): Used simply for producing frequency signals. (Would you know its internals?)
for further internals pls use google,
i can tell you that as mobile phone usees a lot of digital circuit, and all digital circuits need a basic clock to function, this clock is uesd ad ref for all kind of digital processing. so a main xtal is used for this function


aliarjun 06-17-2009 09:16

Crystal (Quartz) :- It is type of rock with different property. it has ability to generate pulse (beat) while pressing/compacting the rock. that pulse is further processing through IC and used as rtc (real time clock) or for producing radio frequency.

wirefree 06-19-2009 00:55

Appreciate your comments & corrections, Ashwani.

Further to your explanations, concerns regarding the following components become ostensible:

1) Diode Rectifier correctly identified as a Capacitor: Its purpose, individually evaluated, is understood by your explanation. However, for the system seen collectively, what role does it play in the RF circuitry? (Note that its proximity to all RF components prompts this query.)

2) RF IC: The complexity of the received signal that you referred to is a function of modulation. This is required to be "demodulat[ed] so that intelligence in the signal can be extracted'". This is understood. However, could I get you to confirm that the primary purpose of modulating the signal in the first place essentially is better utilization of RF by compressing more data bits into the available RF space.

Look forward to your prompt response and thank you once again for your time & inputs.

Best regards,

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