# Search results

1. ### Group delay related question

my prof ask me to calculate the phase of each wavelength from a relationship between group delay and wavelength: τ = A(λ-λo) τ: group delay λo = 1550nm λ: arbitrary wavelength in nm A: coefficient in ps/nm This formula shows us how to calculate the group delay, corresponds to a wavelength...
2. ### Which mathematical model is suitable for modelling a thin-film optical filter?

Recently, In DWDM systems, they use thin-film optical filter to construct OADM or OXC. I want to ask some expert here, in simulation, which mathematical model is suitable for modeling this type of filter used in optical network, and why?
3. ### Butterworth filter design problems? Need your help

I understand well the aspect mathematic of butterworth filter. My problem now is, how to calculate the coefficients of the denominator of the transfer function in s-domain of an analog butterworth filter without looking up in the table? Of course, we are given a fomula to calculate the poles...
4. ### Looking for info about optical filters

I want papers, books or articles on optical filters. If someone here has been working on this field, please share with me some documents and your experiences??? In addition, have you got some docs on Wavelength-Selective-Switch (WSS), please share here with us. I will not forget the HELP button ;)
5. ### Software for antenna design simulation

I have a small project on microstrip antenna design and my prof recommend me ADS for simulation but it's too expensive to buy for a student. I asked him for a copy with my own PC but he refused and recommended me to work in his Lab. It takes time and I want to do this project in my home. Do you...
6. ### Questions on MSP430 about Program Counter, constant generator and bootstrap loader

I'm reading a book on MSP430 1. There's a phrase I do not understand: Why does Program Counter (PC) increment by 2 not by 1? 2. R2 and R3 act as a constant generators, what are the roles of constant generator? We can generate a constant by using an instruction like ADD or MOV? 3. What is...
7. ### What is it? Rogen's gradient projection

I'm a telecom engineer but I meet this definition in an article. Can some one explain to me the very basics about it or recommend me some lectures that deal with it??? Thank you in advance!
8. ### some beginner-level questions on uE?

1- Recently, What is the technology to produce a memory? I read an article about memory advancement but I do not understand it completely. It talks about NOR-gate and NAND-gate based technology but I dont know about this technology. Can some one here show me the answer as clear as possible...
9. ### Some very basic questions on antenne

- I know why we have to match the impedance of the generator and the one of the antenna. That is to done to get the most power of the generator at the antenne for radiate. Is this true? - I know about the Dipole but I dont know why if we do not have a coaxial connector, we have to use BALUN...
10. ### What is coherent bandwidth, ISI and equalization?

I'm studying digital communication where I have met many new concepts (I used to be a electronic engineer) - What is coherent bandwidth? - what is ISI? - what is equalization I really need your helps because the final exam is coming :( Thank you in advance! Added after 2 hours 39 minutes...
11. ### USB interface question

I need your help in this project - I have a barcode scanner with USB port. - I need to write a program in VC++ in order to read the data from this barcode scanner. I have done easily with COM-port barcode scanner but with this USB-type, I have no idea where to begin because I'm not familiar with...
12. ### Can data be transfered via USB using VB?

USB and VB Is this possible to send data via USB port using Visual Basic 6? I urgently need your help!