RF面试一些必问的问题(转)

magicdog

* IP3
- What is IP3? Why is it important?
- Why is it important?
- How to measure IP3? (use a coupler to add the two input tones together)
- IIP3 vs OIP3? (IIP3(dBm) = (A_W1,W2(dB)-A_IM3(dB))/2 +P_in(dBm), OIP3(
dBm) = (A_W1,W2(dB)-A_IM3(dB))/2 +P_out(dBm), OIP3(dBm)-IIP3(dBm) = G(dB))

* Noise Figure
- What is Noise Figure?
- What is Noise Figure of multi-stage LNA?
- How to measure Noise Figure? (1.Noise figure meter. 2.Total gain method
. 3. Y-factor)
- Remark: F (Noise factor, linear), NF (10logF, logarithm)

* What are main parameters of LNA? (Gain, NF, IP3, P1dB, ) How to measure
them?

* How to design a two-state LNA? (trade-off between gain and noise figure)

* Receiver:
- The architecture of Superheterodyne Receiver.
- The architecture of Homodyne Receiver.
- Parameters of the receiver. (NF, G_t(transducer power gain), IP3 (why
is it import), )

* Matching network:
- LC component match:
- Shunt Stub transmision line:
- Try the cases: 1. 25+j25 Ohm --> 50 Ohm. 2. 50Ohm --> 25Ohm.)

* Filter: esp. 1st order HPF, LPF and BPF. What will step function be like
after LPF, HPF?

* Automatic test softwares: LabVIEW, HPV or CVI.

* Oscillator:
- Basic working theory of Oscillator.
- Phase noise.

* Spectrum Analyzer:
- Basic working theory. (first use a mixer to down-convert RF signal to
DC band.)
- What is Resolution Bandwidth?

* GSM and CDMA.

＝＝＝＝＝＝＝＝＝RF 其它问题：＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
* Transmitter architecture: Why does the transmitter not care the noise so
much?

* Modulation theory:

* PLL architecture:

* IP2: What is IP2?

* Basic statistics: Gaussian distribution.3Sigma.

lzheng1984

学习下，看来基础知识是一定要掌握牢固的！

nmdb123

好好好好好好好好好好好好好好好好好好好好

jumble

基础的东西，俺还不懂啊

tayo134

thanx

luyan

好啊谢谢了

xiaobenyi

大部分都不懂，怎么办？

sprinkler

果然基础!

ben726

虽然都是基础但是都很重要
应是rf工程师都应有的知识

dennischen06

thanks...