in [DSP]

Prev: LDPC code
Next: interfacing three adau1701
From: Rune Allnor on 16 Feb 2010 14:36 On 16 Feb, 19:10, dbd <d... (a)ieee.org> wrote:> On Feb 16, 9:26 am, Randy Yates <ya... (a)ieee.org> wrote:> > > dbd <d... (a)ieee.org> writes:> > > [...] > > > That doesn't give us any options. > > > As Spock once said in Star Trek TOS, "There are always options." > > That's because Spock knew what skills and tools he had available to > apply. Nope. That's because the *authors* behind star trek knew Spock needed a way out whenever he was placed in what seemed, to the unitiated eye, to be a perdicament. In real life, one occationally ends up in situations where, whether one knows one's tools or not, have no way out - except leaving the job. Those kinds of things are known as 'idiot projects', althought exactly *who* is the idiot is not always immediately clear. Rune
From: dbd on 16 Feb 2010 16:49 On Feb 16, 11:36 am, Rune Allnor <all... (a)tele.ntnu.no> wrote:> ... > Nope. That's because the *authors* behind star trek knew Spock > needed a way out whenever he was placed in what seemed, to the > unitiated eye, to be a perdicament. > > In real life, one occationally ends up in situations where, > whether one knows one's tools or not, have no way out - except > leaving the job. > ... > Rune But Rune, leaving the job is an option, and perhaps the best given the skills and tools involved. Dale B. Dalrymple
From: Rune Allnor on 16 Feb 2010 16:55 On 16 Feb, 22:49, dbd <d... (a)ieee.org> wrote:> On Feb 16, 11:36 am, Rune Allnor <all... (a)tele.ntnu.no> wrote:> > > ... > > Nope. That's because the *authors* behind star trek knew Spock > > needed a way out whenever he was placed in what seemed, to the > > unitiated eye, to be a perdicament. > > > In real life, one occationally ends up in situations where, > > whether one knows one's tools or not, have no way out - except > > leaving the job. > > ... > > Rune > > But Rune, leaving the job is an option, and perhaps the best given the > skills and tools involved. I know. Been there - one that. One doesn't want to hang too long around morons and idiots. Before one knows it, one's name is associated with their level of skills and (in)competence. Rune
From: zafaryaar on 19 Feb 2010 03:07 >On Feb 15, 2:06=A0pm, "zafaryaar" <zafargro... (a)gmail.com> wrote:>> Hi, >> >> I'm new to DSP and i have been given a task to do simulation of Digital >> Beam forming using Uniform Concentric circular arrays. >> >> I have to generate (by simulation) multiple adaptive spots beams on earth >> by using Uniform Concentric circular array antenna on satellite. >> >> Some main things to do are; >> >> 1: generate multiple spot beams on earth for mobile communication. >> 2: Uniform Concentric circular array antenna has variable number of anten= >na >> =A0 =A0elements in each ring >> 3: Generated beams could be steered in specific directions >> 4: sidelobe levels should be minimized >> >> I was reading below mentioned paper ( i need to implement this kind of >> approach for satellite) >> >> "A novel wormy cellular structure for high altitude platforms mobile >> communications" by Yasser Albagory >> >> I have to show some results to my professor till end of February but I >> don't know how to proceed. If any one could help me out and tell me what >> steps to follow and how to do it. I will be really thankful. > >How about implementing one of the beamformers in Refs 6 to 9 of your >article? > >You haven't told us anything about the tools and skills available to >apply to the task. That doesn't give us any options. > >Dale B. Dalrymple >@ Dale Hi, I want to use Matlab to get the results. In this paper they gave the formula as: W(θ, φ) =[w1(θ, φ),w2(θ, φ), . . . ,wm(θ, φ), . . . ,wM(θ, φ)] where, wm(θ, φ) = αm dm(θ, φ) , m = 1, 2, . . . , M αm is a window function used for sidelobe reduction dm(θ, φ) is the mth column in the cell-shaping matrix given by D(θ, φ) =d1(θ, φ), d2(θ, φ), . . . , dm(θ, φ), . . . , dM(θ, φ) array steering matrix AS(θ,φ)=S1(θ, φ)S2(θ, φ) · · · Sm(θ, φ) · · SM(θ, φ) where, Sm(θ, φ) =ejkrm sin θ cos(φ−φm1)ejkrm sin θ cos(φ−φm2) · · · ejkrm sin θ cos(φ−φmn) · · · ejkrm sin θ cos(φ−φmNm )T Array factor AF(θ, φ) = SUM W(θ, φ)H * AS(θ, φ) How should I proceed to get result from above formulas and calculate the array factor of Uniform Concentric circular array in Matlab. I don't understand by Skills (do u mean my skills or how many people are engaged in this, i m the only one to do this work).Problem is that I have very basic ideas about signal processing and Matlab. thanks.
From: Rune Allnor on 19 Feb 2010 03:40
On 19 Feb, 09:07, "zafaryaar" <zafargro... (a)gmail.com> wrote:> How should I proceed to get result from above formulas and calculate the > array factor of Uniform Concentric circular array in Matlab. I don't > understand by Skills (do u mean my skills or how many people are engaged in > this, i m the only one to do this work).Problem is that I have very basic > ideas about signal processing and Matlab. Matlab might be only one of your problems. You list a number of parameters and expressions. Do you understand what they various factors are? What physical effects are at play? Why you need sidelobe reduction? Matlab is just a computational tool to help you do the drudgery. *You*, the analyst, neds to know not only *what* to do and *how* to do it; it is at least as important to understand *why* you do things. I suspect you might find that once you understand the 'what' and 'why', the 'how' is trivial. There aren't too many ways around this but to read the literature and contemplate what you read. Rune |