Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by jsolar

  1. jsolar

    Can I do this without looping?

    This is a fundamental problem with non-linear elements in a feedback path. You will not be able to vectorize. You might try an old trick though. Instead of having to make a sample by sample decision you could make small block decisions. This has been used in practice for exactly your...
  2. jsolar

    Life, The Universe, and Everything

    SomeptingGuy, sum times you find out somehing interesting. Thanks, I write an informal MATLAB user group newletter aperiodically. I a always looking for something interesting and of general interest. I appreciate it! John Solar
  3. jsolar

    Signal Processing Problem

    Correct. Mostly. The frequencies are true, since the transform shows or lists all of the frequencies possible. The amplitudes are incorrect, but the best based on the assumptions about what happens outside of the time sample we used. This happens even when there is no modulation, so modulation...
  4. jsolar

    The passing of an unsung hero

    All, Nice work and well written. Thanks for kicking it off jraef
  5. jsolar

    Connecting VCOs for generating RF signals

    You have wire OR'ed an RF connection. At your frequencies you need to have impedence control and matching. The vendor does not specify the output Z when not powered, so you do not have the information to make a decision. Past work has shown that non powered ckt.'s can still look like diods...
  6. jsolar

    amplitude frequency response using fft

    The numeric values of the Fourier transform are identintical. It is just that the numbers on your frequency axis are now cut in half. Whereas originally you might have plotted them from zero to 0.5 Hz, you would now plot from zero to 0.25 Hz.
  7. jsolar

    Complex numbers for embedded matlab for simulink

    try log( abs( stuff ) ) or find all of the non positive elements of stuff using find() and setting them to eps.
  8. jsolar

    Design of a wireless comms system

    Your last and final touching of modulation should be your physical layer encryption. Do this with a spreading code, preferably a CDMA type phase modulation (see the 3G recommendations, they are very good ideas). At 0.1 Gbps raw data rate, assuming 4X spreading and final 20 dB spread you will...
  9. jsolar

    nn toolbox & transfer function

    The NN toolbox is available
  10. jsolar

    impedance matching

    VE1BLL is correct. There is no such thing as two antenna's close together. You can not cheat physics. You will have coupling, intended or otherwise. Why do you have 2 apertures close? What effect are you intending to acheive?
  11. jsolar

    Breaking Ohm's Law

    rifter1 "Ohms law stating that current is directly proportional to voltage" is true only for a resistive load. As soon as there is any reactance there is a phase angle between voltage and current. There is a diffeence between VA and VAR.
  12. jsolar

    Frisbee locating device

    If you can afford an elaborate "finding" device, like at a disc golf club, you might try a diode. By selecting the lead length on a high frequency diode you can make a zero power transponder. With a lot of power and some directivity on a powered "finder" you would transmit an RF signal n a GHS...
  13. jsolar

    Please Help!!!

    Whatever it is you are heating, you will need to know its specific heat (you have already given the volume as 2mm, so is that a 8 cubic mm?). Then you will need to explain to us the method of conduction and efficiency into this material. With unfounded assumptions on the specific heat and on...
  14. jsolar

    Field Strength vs. reciever sensitivities

    Higgler is correct. To elaborate more, you are asking for a comparison between apples and oranges, or more precisely between power density and power. The field strength meter will tell you how many volts per meter the filed pressure is. With an assumed far field free space estimate of 120 *...
  15. jsolar

    Low SNR PLL

    johnwiss, Good work. The recycled preamble sound like the key to your innovation. Averaging (of any sort, Kalman or otherwise) does not really help when you are below threshold (the point where the output SNR drops drastically with dropping input SNR). The cycle slips averaged give bad data...
See more

Part and Inventory Search

Back
Top