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  1. #1
    ChaosThyre81
    Guest

    I understand that analog uses more power than digital. Is this because
    the transmitter is always on, where as with digital the transmitter is
    only on part of the time? Like on for 1, off for 0? Something like
    that? TDMA phones seem to have a problem with making speakers buzz as
    the transmitter goes on and off. But why doesn't any phone that's
    digital do this? Like CDMA, the transmitter is turning on and off
    rapidly as it's sending out it's info, why doesnt that make the
    speakers make a funny buzzing noise?

    Thanks!

    Mike


    --
    ChaosThyre81



    See More: Analog VS Digital Question




  2. #2

    Re: Analog VS Digital Question

    On Wed, 16 Mar 2005 05:36:35 +0000, ChaosThyre81
    <[email protected]> wrote:

    >I understand that analog uses more power than digital. Is this because
    >the transmitter is always on, where as with digital the transmitter is
    >only on part of the time?


    Output power spec is higher. Digital designers thought they could cut
    corners and get moredata into less bandwidth and power. Listen to one of
    each, then you'll see that compromises were made.

    <snip>
    > TDMA phones seem to have a problem with making speakers buzz as
    >the transmitter goes on and off. But why doesn't any phone that's
    >digital do this? Like CDMA, the transmitter is turning on and off
    >rapidly as it's sending out it's info, why doesnt that make the
    >speakers make a funny buzzing noise?


    CDMA uses an entirely different modulation system than GSM & TDMA (which
    are very similar) and its emissions just aren't as strong, so it interferes
    much less.


    --
    The TSA is a test. It is only a test......
    "Find out just what people will submit to, and you have found out the exact amount of injustice and wrong which will be imposed upon them; and these will continue until they are resisted with either words or blows, or with both. The limits of tyrants are prescribed by the endurance of those whom they oppress." -- Frederick Douglass, August 4, 1857.
    John Bartley, K7AAY, PDX OR USA, Opinions mine.



  3. #3
    Tropical Haven
    Guest

    Re: Analog VS Digital Question

    >>I understand that analog uses more power than digital. Is this because
    >>the transmitter is always on, where as with digital the transmitter is
    >>only on part of the time?

    >
    > Output power spec is higher. Digital designers thought they could cut
    > corners and get moredata into less bandwidth and power. Listen to one of
    > each, then you'll see that compromises were made.
    >
    > <snip>
    >
    >>TDMA phones seem to have a problem with making speakers buzz as
    >>the transmitter goes on and off. But why doesn't any phone that's
    >>digital do this? Like CDMA, the transmitter is turning on and off
    >>rapidly as it's sending out it's info, why doesnt that make the
    >>speakers make a funny buzzing noise?

    >
    > CDMA uses an entirely different modulation system than GSM & TDMA (which
    > are very similar) and its emissions just aren't as strong, so it interferes
    > much less.


    I'm not technical enough to know, but I have heard that CDMA does have
    interference, but it is more random and not patterned as much as TDMA
    based devices (TDMA/GSM/iDEN). It sounds like it could be possible, but
    I truly have no idea.




  4. #4
    CharlesH
    Guest

    Re: Analog VS Digital Question

    Joseph wrote:
    > On Wed, 16 Mar 2005 05:36:35 +0000, ChaosThyre81
    > <[email protected]> wrote:
    >
    >>TDMA phones seem to have a problem with making speakers buzz as
    >>the transmitter goes on and off. But why doesn't any phone that's
    >>digital do this?

    >
    > GSM also causes RF interference when transmitting especially when a
    > GSM handset is ringing.


    GSM, U.S. "TDMA" (IS-136), and iDEN (Nextel) use Time Division Multiple
    Access air protocols. This means that they they get a time slice during
    which they transmit and receive. All of the power has to go into this
    narrow pulse. This pulsing several hundred times per second is what
    causes the interference with speakers and other equipment.

    When a CDMA (Code Division Multiple Access) phone is in a call or doing
    other occasional chit-chat with the system, it is transmitting
    continuously at a very low power level with the signal spread across a
    wide band (1.25MHz for the current CDMA systems). They are very unlikely
    to cause interference; in fact, without knowing the specific coding
    parameters for that particular call, it is very difficult to distinguish
    the signal of a CDMA phone from background noise even with sophisticated
    receivers, let alone for it cause interference with random equipment.



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