Sökning: "bandwidth expansion"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden bandwidth expansion.

  1. 1. Source-Channel Coding in Networks

    Författare :Niklas Wernersson; Mikael Skoglund; Geoffrey Chan; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source coding; channel coding; joint source-channel coding; bandwidth expansion; distributed source coding; multiple description coding; soft decoding; Telecommunication; Telekommunikation;

    Sammanfattning : The aim of source coding is to represent information as accurately as possible using as few bits as possible and in order to do so redundancy from the source needs to be removed. The aim of channel coding is in some sense the contrary, namely to introduce redundancy that can be exploited to protect the information when being transmitted over a nonideal channel. LÄS MER

  3. 2. Integrated Transmitters for Cellular User Equipment–Wideband CMOS Power Amplifiers and Antenna Impedance Tuners

    Författare :Jonas Lindstrand; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CMOS; LTE; Impedance tuner; Injection lock; Power amplifier; Efficiency; Polar bandwidth expansion; multiband;

    Sammanfattning : The digital cellular systems era started about thirty years ago with the release of the first digital cellphones. These first digital cellphones were very different from today’s slim and esthetic cellular pocket computers. They were not mass-produced in million units a day, and they were designed for radio performance rather than appearance. LÄS MER

  4. 3. Error Correction Coding for Optical CDMA

    Författare :Henrik Lundqvist; KTH; []
    Nyckelord :;

    Sammanfattning : The optical fiber is a very attractive communication mediumsince it offers a large bandwidth and low attenuation and cantherefore facilitate demanding services such as high-qualityvideo transmission. As the reach of optical fiber is beingextended to the access network it is economically attractive toshare fibers between different users without adding activecomponents in the network. LÄS MER

  5. 4. Efficient 1.3 mm GaInNAs Quantum Well Lasers for Uncooled, High Speed Operation

    Författare :Yongqiang Wei; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor laser; uncooled; temperature dependence; modulation; quantum well; molecular beam epitaxy; high speed; GaInNAs;

    Sammanfattning : The rapid expansion of tele and data transmission systems requires an ever increasing capacity in modern optical fibre communication networks. With the implementation of short distance, high density networks, such as access networks, there is a need for cost-effective optical transmitters compatible with single mode fibres. LÄS MER

  7. 5. Linearization of High Efficiency Transmitters for Wireless Communications

    Författare :Haiying Cao; Chalmers University of Technology; []
    Nyckelord :dynamic load modulation; Behavioral model; digital predistortion; I Q imbalance; Volterra series; efficiency; power amplifier; transmitter;

    Sammanfattning : In recent years, reducing energy consumption in wirelesscommunication systems has gained prominence. In order to achieve this energy saving, high power efficiency is necessary for the wireless transmitters used. LÄS MER