# Recent content by ermai

1. ### Question about low noise figure

https://rickettslab.org/wp-content/uploads/2016/01/LNA_noise_design.pdf As the equation (14) in the above link , the noise In can be separated to Inu and Inc ,and Inc is correlated to Vn theoretically. My question is how to get the correlation between Inc and Vn in practice? Is it...
2. ### What is "TWO-TONE SFDR" meaning?

https://imgur.com/a/08deP I figured it out !!!It is from the image of negative fs !!!
3. ### What is "TWO-TONE SFDR" meaning?

Thanks.So it deduces that the f1=169.6MHz@-7dBFS and f2=170.6MHz@-7dBFS. produce the noise pattern in figure 23 under Fs=130MHz? But if the Fs=130MHz, then the image should be located at 2x130Mhz -170.6Mhz=89.4Mhz, however in figure 23 , the -7dB is at between 31.250 - 46.875Mhz, I can't...
4. ### What is "TWO-TONE SFDR" meaning?

https://www.analog.com/media/en/technical-documentation/data-sheets/AD9461.pdf In the ADC datasheet , it depicts that ======================================= TWO-TONE SFDR fIN = 169.6 MHz @ 7dBFS, 170.6 MHz @ 7dBFS ======================================= what is it meaning here?what is the...
5. ### What is low background Iddq in device?

https://books.google.com.tw/books?id=ymMmoP-hAGkC&pg=PA18&lpg=PA18&dq=iddq+iv+curve&source=bl&ots=XzCOXsPcIj&sig=VyhGJqDlcY3Z6gGx7W7Qq4phw6A&hl=zh-TW&sa=X&ved=0ahUKEwjgm7PWqMbZAhVInpQKHSigCvAQ6AEILTAB#v=onepage&q=iddq%20iv%20curve&f=false In page 26 of the textbook it depicts that "For...
6. ### Why the long term 1 and 0 number balance affect clock recovery?

As the title,the 1 and 0 sequence number should be balanced to decrease error rate(clock recovery). I would like to know the principle.Thanks
7. ### why does self-complementary antenna have constant input impedance

Dear All: I would like to know the principle of why complementary antenna has a constant input impedance.Could someone tell me or show me the documents?I would appreciate very much
8. ### How do I set to let enclose lines form a surface ?

I have drawn closed line,how do i do to let those lines form a surface
9. ### HFSS, simulation of a single SRR to find resonant frequencies

You could simulate it with lumped port,and see where the z is 0 or infinite(it has chance to be infinite because SRR is a parallel resonator )
10. ### Why does scaling of an antenna through angle make it frequency independent?

I have read Rumsey 's paper about it,but I want to know the physical sense.
11. ### Does a charged capacitor act as a short circuit in feedthrough?

No power supply.Only 2 capacitor. Long story short,my question is "Does a capacitor act as short when the voltage applied to it changes,even a charged capacitor"?
12. ### Does a charged capacitor act as a short circuit in feedthrough?

A capacitor behaves as short when initially uncharged and sudden volatage is applied and open when fully charged. But in feedthrough,a volatge variation is in a charged coupling capacitor. A feedthrough effect by a coupling capacitor is as below: in which C2 is a couplng capacitor to VL2,and...
13. ### How to measure noise of an amplifier?

Because in many textbook,the optimum source impedance is caculated as following https://www.maximintegrated.com/app-notes/index.mvp/id/3169 for the lowest noise factor(this is also depicted in appendix L in Guillermo Gonzalez's "Microwave Transistor Amplifiers: Analysis and Design " ),so I...
14. ### How to measure noise of an amplifier?

https://imgur.com/sJWhV,nXgwu,fEltE,RcbUs,hYuur,t2xvw#0 I have read a textbook above about noise measurement. It depict that we measure Vso(the output voltage of the amplifier) with Rs=0 and get En, and with large Rs get In. and then C with Rs=Ro . But I don't understand why and how we get C...
15. ### How to measure noise of an amplifier?

A noisy network model of an amplifier is below https://imgur.com/gwSqf I want to know how measure In En and C which is correlation between In and En? Thanks.