Recent content by csopi

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    How does the phase noise of the LO effect IF accuracy?

    Many thanks! I have looked into phase noise, and now I understand that I should calculate the total rms phase error, which describes the "average" deviation of the system. And here comes the problem: how to calculate this? I have found various tutorials on manufacturers' website, most of them is...
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    How does the phase noise of the LO effect IF accuracy?

    Hi, I have a roughly 1.1 GHz signal to be downconverted to 100 MHz by mixing it with a 1 GHz local oscillator. I am not sure how to choose the performance of the LO. In particular: let's assume the LO has a jitter of 100 fs rms. At 1 GHz this corresponds to a frequency error of 100 kHz. Does...
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    A Combinatorial optimization problem

    Thanks for the immediate reply! I have heard about this one, actually already tried a basic version. I am wondering if there are other methods? B & B is an "art" for me, not sure what is the most efficient way for bound estimation, that's why I am asking.
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    A Combinatorial optimization problem

    Hi, I have the following optimization problem. I have a list of tasks that I should be able to perform with my tools. Each tool costs a certain amount of money, and may be used to carry out a finite number of tasks. The goal is to choose an optimal set of tools in such a way that the toolset can...
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    Frequency measurement -- how to choose sampling ?

    Hi, let's say I want to measure the frequency f of a periodic signal. I may take N data points with an arbitrary timestep of T. The question is how shall I choose T for a fixed N to have the best accuracy? In principle the frequency resolution is 1/(N*T) when taking the Fourier transform...
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    Complex Numbers problem

    First you should solve the equation for 'a'. After that, you can calculate the argumentum and the abs. value of 'a', resulting in a = r*(cos(theta) + i* sin(theta)). Finally, apply De Moivre for calculating a^2011.
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    MRI technology

    Hi all, I am wondering about the actual technological parameters of a modern MRI. In particular I mean sensitivity, i.e. the order of magnitude of the signals to be detected and the noise levels in practice. Can somebody recommend a good reference about the subject from an engineering...
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    Infinite square well solution

    You have thought it right, 'A' can be complex indeed. In fact, A=\sqrt\frac 2 a\,e^{i\phi} satisfies the the normalization constraint for any real \phi. Mind that the phase of the wave function is arbitrary.
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    Good thermal conductor but insulator

    Good idea, but unfortunatelly this won't solve my problem. I'll use it as a sample holder at 4 K, and it'll be subjected to AC magnetic fields. The aim is to get rid of the eddy currents and for this I need the bulk to be an insulator as well.
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    Good thermal conductor but insulator

    Thank you very much for your help, I'll look into the hints!
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    Good thermal conductor but insulator

    Hi, Does anybody know a material which is a good thermal conductor and an insulator at the same time (at temperatures around 4 K) and is "easy" to fabricate? For e.g. sapphire fulfils the first two requirements, but is extrmely hard.
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    Clarifications regarding definitions of Taylor, Laurent etc. series

    Here are some crucial differences: 1. A Laurent series is convergent on an annulus in the complex plane, whereas the Taylor series is on a disk. 2. EVERY function that is holomorphic on r < | z - a | < R has a unique, convergent Laurent series (defined on this disk. The exact values of the...
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    Clarifications regarding definitions of Taylor, Laurent etc. series

    Here are some crucial differences: 1. A Laurent series is convergent on an annulus in the complex plane, whereas the Taylor series is on a disk. 2. EVERY function that is holomorphic on r < | z - a | < R has a unique, convergent Laurent series (defined on this disk. The exact values of the...
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    Designing a microwave cavity

    Thank you, I'll look into it! Just out of curiosity: do you know any open source alternative?
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    Designing a microwave cavity

    Hi all, I need a proper software for designing microwave cavities. I intend to use simple base geometries (e.g. closed box) with some modifications, like holes for optical access or for feeding the MW. These modifications however may seriously affect the Q factor, the frequency or might...
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