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Recent content by johnwiss

  1. johnwiss

    Sampling system SNR and SFDR

    The fact that every 4x reduction in digital filtering and resampling buys an extra bit of the ADC is true for flash / pipeline ADCs--for sigma delta adcs you get much more. You need a filter with a gain of 2 to exploit the extra bit. Processing gain or spreading gain also builds SNR but after...
  2. johnwiss

    Does your company montitor Internet Usage?

    most "large" (>1000 employees) do attempt to log websites visited by employees and can search for keywords in emails. There are ways to make the logging harder---for example if you can "turn off the "automatically detect proxy settings" tab in in you tools internet options, Lan setting tab in...
  3. johnwiss

    Filters in control systems

    The filter in conjunction with the feedback makes a transfer function that has the form Y=G(s)H(s)/{1+G(s)H(s)} where we are forming a control system with a plant H and a "filter" or "loop filter" G. The expression is the Laplace transform of the (usually) differential equations...
  4. johnwiss

    Signal Processing Problem

    It is really simple--FFTs are great but you need to understand what they are doing. The are a way of calculating a Discrete Fourier Transform (DFT) using some calculation tricks to compute the transform with a Ncalc = cN*LOG(kN)type relationship between the size of the transform (N) and the...
  5. johnwiss

    Hughes Directway Internet Satellite

    I have heard lots of issues with VPN problems using true satellite 2-way communications. Part is due to some of the issues mentioned above (pseudo-networks, no static IP capability etc.) The other issue is latency and unfortunately god and our choice of planet are to blame. The satellites...
  6. johnwiss

    Link Budget

    I think dBi should be about 2.5 dB less than dBd--is that what the specs show??
  7. johnwiss

    Lacking confidence in my position

    First a few questions Airforce2: How many years are you in your profession? If you are a newbie and you work in isolation how do you expect to increase your competence in your job? What are you consulting for if you are a newbie? Consultants in my field tend to be very experienced. I do...
  8. johnwiss

    What is the best engineering advice you ever received?

    Inevitably, the easy things are where the bugs are. So when it comes to designing you must sweat the little stuff!! "Good enough" is perfect. The bug just introduced is your bug--it is not a compiler bug, a subtle bug, it is a bleeding obvious one--so question thyself first. John
  9. johnwiss

    Need an honest answer

    Wow! lots of opinions. I am a male manager and have two women in my group--they are excellent and any male boss who has a problem treating women as equals needs to be gotten rid of--through human resources. I think if he is reasonable the following logic applies: Most bosses put people on...
  10. johnwiss

    How far do you commute?

    some people really have it made commute-wise :) I am probably average with 20 miles each way and about 35-mins each way. Anything consistently over an hour calls for flexible start times to avoid peak traffic periods -- two hours of your life are eaten right out of your day and any more is a...
  11. johnwiss

    Engineers on time clock

    I think these precedents suck! They probably monitor web usage (usually the domains you are visiting), email, phone calls, now they are monitoring wxactly how long you are at the plant. You should get the younger folks to lobby for telecommuting at least a day or so each month at first, then...
  12. johnwiss

    Titles: Engineer vs. Designer

    Got the same issue--I am the Director of Signal Processing Design, when in fact my group sohould be called Communcations systems Engineering since we are the best engineers in the division and do that function. Problem is there is another group with the systems engineering moniker--so they had...
  13. johnwiss

    Temporary measure or a kick in the teeth?

    Please don't take this the wrong way but your boss was evidently one step away from a job that has the whole department reporting to him. You are a newbie by anyone's standards. Do you think you can run the whole department in another three years? If so then leave. If not, ask to participate...
  14. johnwiss

    Low SNR PLL

    jsolar, Phase detector is just Err = Q*sgn(I) - I*sgn(Q) which is the maximum likelihood solution for QPSK. The fundamental problem is that you would like to average to get a lot of noise rejection into the loop. The issue is averaging implies delay, which is always bad in a feedback loop...
  15. johnwiss

    Lack of Self-Confidence at work

    The very fact that you are feeling this way means you are probably going to do quite well--it means you know what you don't know and you are being challenged. Find a good mentor who knows more than you and learn like a sponge. People I have worked with who are new and think they know it all or...
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