Sökning: "low noise amplifier"

Visar resultat 21 - 25 av 70 avhandlingar innehållade orden low noise amplifier.

  1. 21. Low Noise Amplifiers Based on High TC SQUIDs

    Författare :Jakob Blomgren; Chalmers University of Technology; []
    Nyckelord :;

    Sammanfattning : This thesis describes the development, fabrication, performance and applications of liquid nitrogen cooled voltage amplifiers based on high temperature superconducting quantum interference devices (SQUIDs). The SQUID based voltage amplifier is intended for characterization of electrical and noise properties of devices with resistance around and below 1 Ohm. LÄS MER

  2. 22. Low Noise Oscillator in ADPLL toward Direct-to-RF All-digital Polar Transmitter

    Författare :Jian Chen; Li-Rong Zheng; Fredrik Jonsson; Hannu Tenhunen; Georges Gielen; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; all-digital; digitally-intensive; frequency modualtion; phase modulation; amplitude modulation; polar; transmitter; oscillator; digital controled oscillator; DCO; VCO; voltage controled oscillator; class-C oscillator; class-D PA; ADPLL; phase noise; RF; CMOS.;

    Sammanfattning : In recent years all-digital or digitally-intensive RF transmitters (TX) have attracted great attention in both literature and industry. The motivation is to implement RF circuits in a manner suiting advanced nanometer CMOS processes. To achieve that, information is encoded in the time-domain rather than voltage amplitude. LÄS MER

  3. 23. Ultra-Wideband Low-Noise Amplifier andSix-Port Transceiver for High Speed DataTransmission

    Författare :Adriana Serban; Shaofang Gong; Ke Wu; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : Today’s data rates in wired networks can reach 100 Gbit/s using optical fiber while data rates in wireless networks are much lower - tens of Mbit/s for 3G mobile communication and 480 Mbit/s for ultra-wideband (UWB) short range wireless communications. This difference in data rates can mainly be explained by the limited allowed frequency spectrum, the nature of the radio signal and the high requirements imposed on all hardware designed for high speed and wideband wireless communications. LÄS MER

  4. 24. Continuous-Time Delta-Sigma Modulators for Ultra-Low-Power Radios

    Författare :Dejan Radjen; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Delta-Sigma; continuous-time; analog-to-digital; ultra-low-power; clock jitter; single operational amplifier; SAR quantizer;

    Sammanfattning : The modern small devices of today require cheap low power radio frequency (RF) transceivers that can provide reliable connectivity at all times. In an RF transceiver, the analog-to-digital converter (ADC) is one of the most important parts and it is also one of the main power consumers. LÄS MER

  5. 25. Radio Frequency Systems for NMR Imaging: Coil Development and Studies of Non-Thermal Biological Effects

    Författare :Lars Malmgren; Lunds universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; anechoic chamber; TEM transmission cells; FDTD; circularly polarized electromagnetic fields; reduced coupling; noise matching; matching networks; low noise amplifiers; upper thoracic spine; surface coils; Nuclear magnetic resonance; magnetic resonance imaging; non-thermal biological effects; blood-brain barrier; Electronics; Elektronik;

    Sammanfattning : This thesis concerns both design and optimization of NMR imaging systems and studies on non-thermal biological effects of electromagnetic fields. These two research fields are linked together by the fact that humans are subject to static and pulsed magnetic fields as well as to magnetic radio frequency fields (RF) during an NMR imaging investigation. LÄS MER