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Method and arrangement for transmitting and receiving RF signals through various radio interfaces of communication systems

  • US 8,755,834 B2
  • Filed: 09/13/2012
  • Issued: 06/17/2014
  • Est. Priority Date: 11/26/1998
  • Status: Expired due to Term
First Claim
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1. A direct-conversion transmitter comprising:

  • a digital signal processor;

    a digital-to-analog converter configured to convert a digital baseband quadrature signal to an analog baseband transmission signal;

    a transmit synthesizer common to a plurality of radio interfaces of the direct-conversion transmitter and configured to generate a mixing signal;

    a controllable low-pass filter common to a plurality of radio interfaces of the direct-conversion transmitter, the controllable low-pass filter configured to perform filtering of the analog baseband transmission signal with a controllable cut-off frequency determined according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected;

    a frequency divider common to the plurality of radio interfaces of the direct-conversion transmitter and configured to divide a frequency of the mixing signal at least by two, wherein the dividing produces two mixing signal components having a 90-degree phase difference;

    a controllable gain transmitter amplifier common to the plurality of radio interfaces of the direct-conversion transmitter and configured to amplify a carrier-frequency signal from a mixer of the direct-conversion transmitter at a gain controlled according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected; and

    an antenna,wherein at least one of the plurality of radio interfaces of the direct-conversion transmitter comprises a modulation, a channel spacing, and a channel bit rate that at least one other of the plurality of radio interfaces does not have.

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