Any question about Wireless Technology

[lordofearrings]

If any one has any question about wireless technology, go ahead and raise your question, I would be happy to answer all if they are within my knowledge (remember: all questions are in English).

[7604]

8

[lordofearrings]

7604,
This is not a question, but a PROJECT. I don't have much time sitting and thinking. Sorry!

[7604]

5

[lordofearrings]

- what is the phase lock loop frequency in Nokia highband TDMA moble phone and how it work?

A phase-locked loop (PLL) is an electronic circuit with a voltage- or current-driven oscillator that is constantly adjusted to match in phase (and thus lock on) the frequency of an input signal. In addition to stabilizing a particular communications channel (keeping it set to a particular frequency), a PLL can be used to generate a signal, modulate or demodulate a signal, reconstitute a signal with less noise, or multiply or divide a frequency. PLLs are frequently used in wireless communication, particularly where signals are carried using frequency modulation (FM) or phase modulation (PM). PLLs can also be used in amplitude modulation (AM). PLLs are more commonly used for digital data transmission, but can also be designed for analog information. Phase-locked loop devices are more commonly manufactured as integrated circuits (ICs) although discrete circuits are used for microwave.
A PLL consists of a voltage-controlled oscillator (VCO) that is tuned using a special semiconductor diode called a varactor. The VCO is initially tuned to a frequency close to the desired receiving or transmitting frequency. A circuit called a phase comparator causes the VCO to seek and lock onto the desired frequency, based on the output of a crystal-controlled reference oscillator. This works by means of a feedback scheme. If the VCO frequency departs from the selected crystal reference frequency, the phase comparator produces an error voltage that is applied to the varactor, bringing the VCO back to the reference frequency. The PLL, VCO, reference oscillator, and phase comparator together comprise a frequency synthesizer. Wireless equipment that uses this type of frequency control is said to be frequency-synthesized.

Since a PLL requires a certain amount of time to lock on the frequency of an incoming signal, the intelligence on the signal (voice, video, or data) can be obtained directly from the waveform of the measured error voltage, which will reflect exactly the modulated information on the signal.

[lordofearrings]

Hey 7604,
Your sentence "I have around ten thousand questions about wireless techology range from general to technical" seems nut to me. Answering a question right is hard, but raising questions is hella easy, 7604. You can copy questions from books, internet,... everywhere to post on here. So don't try to play like a fool here.

I only reply to those who are willing to learn. YOU ARE NOT IN THIS CASE, 7604.

[7604]

2

[lordofearrings]

It's all right.
I know you got lots of experience in your working field. And I can guess your age too. Of course you can ask as many question as you like based on your knowledge. However, you ask but you don't need answers. As a result, you are a BIG DIFFERENCE in this forum... hehe... another meaning... kidda show up.
Forget all da things...
Nice to know ya too.

[Dinhnq]

hey!
760.. la con ADC bao nhieu bit vay, dua ti thoi toi cung rat quan tam ve van de wireless, cho hoi mot chut con PLL co the mua o dau vay, cac ban co tai lieu ve no khong cho minh muon tham khao mot chut .
thank (biet moi cau tieng anh nay thoi, thong cam nhe)

[James Nguyen]

Chao Cac Ban:
Neu Anh ngu khong phai la tro ngai cho cac ban, toi xin gioi thieu voi cac ban mot so web sites nay de cac ban rong duong nghien cuu: http://www.sysopt.com/ (Gom hon 35,000 thanh vien chuyen ve nhung cau hoi lien quan den CCTT) va http://www.pcguide.com/