Search:

Type: Posts; User: senmeis

Page 1 of 4 1 2 3 4

Search: Search took 0.02 seconds.

  1. Replies
    0
    Views
    226

    Closed: TDMA vs. FDMA in Satcom

    Hi,

    I noticed most of the satcom products are TDMA-based. Can anyone explain what is the advantage over FDMA which is also available on the market?

    Senmeis
  2. Replies
    2
    Views
    282

    Closed: Fixed load of wave guide

    Hi,

    how does a fixed load of wave guide (to mitigate reflections) look like, pyramid shape?

    Senmeis
  3. Closed: “curve-fit based” method for III-V devices

    Hi,

    I’ve heard that the commonly used “curve-fit based” method which is valuable for IV-IV semiconductors, is not so accurate for III-V devices such as GaAs. Is this statement correct?

    Senmeis
  4. Replies
    3
    Views
    823

    Closed: Re: I/Q data and envelope

    I think the most important characteristic is, the swings between envelopes must disappear. Can this operation support this?
  5. Replies
    3
    Views
    823

    Closed: I/Q data and envelope

    Hi,

    How to understand this statement:

    The digital processing computes the root sum of the squares of the I and Q data, which is mathematically equivalent to an envelope detector?

    Does it...
  6. Replies
    1
    Views
    861

    Closed: vibration rejection in IMU

    Hi,

    One spec of an IMU is: ±450 deg/s wih high vibration rejection.

    Question: Shall vibration have the unit “deg/s”?

    Senmeis
  7. Replies
    1
    Views
    373

    [SOLVED]Closed: Measurement range of signal analyzers

    Hi,

    the following description is taken from a document of signal analyzers:

    A spectrum analyzer with a 24-dB noise figure will have an average displayed noise level of –110 dBm in a 10-kHz...
  8. Closed: Re: GNSS+INS ultra-tightly coupled navigation system

    I asked this question because of this description „accept NCO commands from external sources“ from the attached slide.

    Senmeis
    152510
  9. Closed: GNSS+INS ultra-tightly coupled navigation system

    is it true, in a GNSS+INS ultra-tightly coupled navigation system the GNSS receiver sampling is controlled by INS output?

    Senmeis
  10. Replies
    2
    Views
    2,090

    Closed: Re: Two scale factors in IMU

    I’m not sure if the „scale factor in-run stability“ is related to the case when the IMU stands still. Attached is an example of both parameters. It seems scale factor in-run stability is measured...
  11. Replies
    2
    Views
    2,090

    Closed: Two scale factors in IMU

    Hi,

    an IMU has two parameters:

    scale factor repeatability = 1000 PPM (1-sigma)
    and
    scale factor in-run stability = 250 PPM (1-sigma)

    Question: What is the difference...
  12. Replies
    0
    Views
    185

    Closed: Digital phasing in feeds

    Hi,

    in this data sheet http://www.tcs.la/Portals/0/TCSFeedsAndRFTechnology.pdf the terminology „digital phasing“ is refered. How does this digital phasing work exactly? Is DSP required for it?
    ...
  13. Replies
    1
    Views
    853

    [SOLVED]Closed: dual axis tracking antennas

    Hi,

    What axes are meant in „dual axis tracking antennas“? Azimuth and elevation? Is there alternative interpretation?

    Senmeis
  14. Replies
    5
    Views
    2,982

    Closed: Re: overhead keyhole question

    In this document it states also:

    Digital demodulation and Autotrack phasing at the controller.

    I think demodulation shall be conducted in a Modem, why controller here?

    Senmeis
  15. Replies
    7
    Views
    2,645

    [SOLVED]Closed: Re: Piezoelectric vs. MEMS accelerometers

    OK, is this understanding correct: PE is better than VC but both can belong to MEMS?

    Senmeis
  16. Replies
    7
    Views
    2,645

    [SOLVED]Closed: Re: Piezoelectric vs. MEMS accelerometers

    Please find the source of this statement in the attachment.

    Senmeis
  17. Replies
    7
    Views
    2,645

    [SOLVED]Closed: Piezoelectric vs. MEMS accelerometers

    Hi,

    Is it correct that piezoelectric accelerometers generally have higher resolution than MEMS ones?

    Senmeis
  18. Replies
    4
    Views
    313

    [SOLVED]Closed: opto for power isolation?

    Hi,

    Can opto isolation only be used for signal isolation or also for power isolation? What about capacitive isolation?

    Senmeis
  19. Replies
    7
    Views
    2,803

    Closed: Re: Tracking in satellite communications

    The technology you described is called “Four Horn Monopulse” in radar tracking. Obviously is operates in RF domain. In radar mono pulses are required. Can this be satisfied in communications?
    ...
  20. Replies
    7
    Views
    2,803

    Closed: Re: Tracking in satellite communications

    But how to intepretate the description “We manufacture autotracking feeds …” if DSP is in charge of autotracking?

    Senmeis
  21. Replies
    7
    Views
    2,803

    Closed: Tracking in satellite communications

    Hi,

    In satellite communications there is a term called “autotracking antennas”.

    My question is, is this tracking capability achieved only by antennas?

    From other sources the feed also...
  22. Replies
    3
    Views
    2,136

    Closed: Re: touch screen in smartphones

    But I have to touch the screen physically to activate it while for capacitive screen it’s not necessary.

    Senmeis
  23. Replies
    5
    Views
    2,982

    Closed: Re: overhead keyhole question

    Do you mean this issue can be eliminated just because the elevation is greater than 90 degree?

    Senmeis
  24. Replies
    3
    Views
    2,136

    Closed: touch screen in smartphones

    Hi,

    Which kind of touch screen is used in smartphones, capacitive or resistive?

    Senmeis
  25. Replies
    5
    Views
    2,982

    Closed: Re: overhead keyhole question

    The following statement comes from the same vendor:

    The systems’ X/Y axis configuration eliminates the keyhole (lost data) effect that occurs with other tracking antennas when satellites pass...
Results 1 to 25 of 98
Page 1 of 4 1 2 3 4