Radio wave transmitter

Discussion in 'Wireless & RF Design' started by anoop6543@gmail.com, Aug 11, 2012.

  1. anoop6543@gmail.com

    Thread Starter New Member

    Aug 11, 2012
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    i am using an texas instruments manufactured EZ430-RF2500T MSP430 2.4-GHz Wireless Target Board and i want to know some general details regarding Rf transmitter ,
    1)will the RF transmitter transmit the waves radially or is there any particular radiation pattern , if so how to check the pattern for a particular RF transmitter.
    2)i am using a transreciever , so now if multiple transmitters are tranmitting the waves at a smae time or within a lapse of some milliseconds ,
    can a reciever in the opposite direction recieve all the transmitter waves or an one wave or no waves due to interference?

    i need the information immediately , can anyone help me very urgent.....................................
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    1) Radiation patterns are determined by the antenna. A quarter-wave vertical, a half wave dipole, and a 13 element yagi will have different 3 dimensional radiation patterns. There is a modeling tool called EZNEC that you can use to develop radiation patterns for various antenna geometries.

    2) Receivers always receive everything that comes in to the antenna. If two signals are different in frequency then one is accepted and the other is rejected (attenuated). A receiver can become desensitized in the presence of a strong RF field even if the receiver is not tuned to the frequency of that strong field.
     
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  3. anoop6543@gmail.com

    Thread Starter New Member

    Aug 11, 2012
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    thanks for ua reply and i need help from u and can u give me ur email id ?
     
  4. bertus

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    Apr 5, 2008
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  5. cork_ie

    Member

    Oct 8, 2011
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    1) Papabravo is dead right - consider a transmitter like a lightbulb - the strength and direction of the light (radio) beam depends on how it is focused. In the case of light waves it depends on lens & reflector with radio waves it is determined by the Antenna design

    2) If you have an identical signal from two different sources on the same frequency you may experience fading (audio) and/or ghosting (video) due to the very slight propagation delay due to the signal taking two or more different paths.
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    Sorry. As a rule I do not like to conduct technical discussions outside of the public forum.
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    From the message that was sent to my email
    It the transmitters all use the same frequency then all of the receivers will receive all of the transmissions. If they contain a unique digital ID then each receiver can discard the messages it does not want if the transmissions occur round robin with several milliseconds of delay.

    If the receivers know the order of transmission then they can have an easier time of picking out the message that they want. How will you keep the transmitters synchronized?
     
  8. anoop6543@gmail.com

    Thread Starter New Member

    Aug 11, 2012
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    actually i am just using the rf transmitter and receiver as a proximity sensor. so i don have to sense which transmitter is transmitting and al, just need a output if a transmitter or transmitters are in the range of a receiver. so will the interference affect my reception to such a extent that it wont receive at all??
    and can anybody have idea about CC110l transceiver (texas instrument product) i want to know whether it does duplexing? ( as it has only one antenna )
    http://www.ti.com/product/cc110l
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    If you are having difficulty understanding how RF transmitters and receivers work, consider the following.

    Imagine you have a room with different coloured LEDs, red, orange, yellow, green, blue, used as transmitters. Along with that you may add a bright room light.

    For the receivers to detect a unique colour you will need coloured filters in front of each photo sensor. Add into the mix multiple remote controllers.

    TV remote controllers use infra-red light to transmit digital codes. Imagine you had multiple remote controllers for TV, VCR, DVD player etc all operating at the same time. All the remotes send the IR signal at the same IR frequency and modulating frequency. Yet each receiver is capable of recognizing the specific transmission from its remote controller.
     
  10. anoop6543@gmail.com

    Thread Starter New Member

    Aug 11, 2012
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    1)yes understood the concept but what we are trying to achieve is, taking your example only lets say there are many bulbs transmitting light and many having same color and a receiver, which has to receive a particular color light only ( i dont care if what its receiving but it has to tel me that there is that particular color emitted light) what my fear is that there may be interference! or may be CC110l(texas Instruments Transciever) may not do what exactly what i want!.


    2)secondly :can cc110l transmit and receive at same time or make it general can a transcevier transmit and receive at same time?


    3) can v use a chip antenna to block ( or detect the rf wave ) in one direction which v decide?
     
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