128,192 research outputs found
Down-converter for GPS applications
An RF down/up converter system is presented for indoor GPS applications. Transmission of GPS signals directly into indoor environments are limited and in some cases prohibited for regular operation of GPS system. However, ISM frequency bands, especially 433MHz can be used to retransmit
the GPS signals to indoors. In this paper, RF down-converter building blocks are designed and implemented for sending GPS signals in ISM band. The down-converter system has heterodyne architecture which has LNAs, mixer, oscillator and filters. Received signals from the satellites are amplified, downconverted, filtered and again amplified. The overall performance of the designed system is 54.3dB gain and 2 dB noise figure while it is drawing 78mA current with 3V supply
Baseband analog front-end and digital back-end for reconfigurable multi-standard terminals
Multimedia applications are driving wireless network operators to add high-speed data services such as Edge (E-GPRS), WCDMA (UMTS) and WLAN (IEEE 802.11a,b,g) to the existing GSM network. This creates the need for multi-mode cellular handsets that support a wide range of communication standards, each with a different RF frequency, signal bandwidth, modulation scheme etc. This in turn generates several design challenges for the analog and digital building blocks of the physical layer. In addition to the above-mentioned protocols, mobile devices often include Bluetooth, GPS, FM-radio and TV services that can work concurrently with data and voice communication. Multi-mode, multi-band, and multi-standard mobile terminals must satisfy all these different requirements. Sharing and/or switching transceiver building blocks in these handsets is mandatory in order to extend battery life and/or reduce cost. Only adaptive circuits that are able to reconfigure themselves within the handover time can meet the design requirements of a single receiver or transmitter covering all the different standards while ensuring seamless inter-interoperability. This paper presents analog and digital base-band circuits that are able to support GSM (with Edge), WCDMA (UMTS), WLAN and Bluetooth using reconfigurable building blocks. The blocks can trade off power consumption for performance on the fly, depending on the standard to be supported and the required QoS (Quality of Service) leve
Basics of RF electronics
RF electronics deals with the generation, acquisition and manipulation of
high-frequency signals. In particle accelerators signals of this kind are
abundant, especially in the RF and beam diagnostics systems. In modern machines
the complexity of the electronics assemblies dedicated to RF manipulation, beam
diagnostics, and feedbacks is continuously increasing, following the demands
for improvement of accelerator performance. However, these systems, and in
particular their front-ends and back-ends, still rely on well-established basic
hardware components and techniques, while down-converted and acquired signals
are digitally processed exploiting the rapidly growing computational capability
offered by the available technology. This lecture reviews the operational
principles of the basic building blocks used for the treatment of
high-frequency signals. Devices such as mixers, phase and amplitude detectors,
modulators, filters, switches, directional couplers, oscillators, amplifiers,
attenuators, and others are described in terms of equivalent circuits,
scattering matrices, transfer functions; typical performance of commercially
available models is presented. Owing to the breadth of the subject, this review
is necessarily synthetic and non-exhaustive. Readers interested in the
architecture of complete systems making use of the described components and
devoted to generation and manipulation of the signals driving RF power plants
and cavities may refer to the CAS lectures on Low-Level RF.Comment: 36 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
Electrically packaged silicon-organic hybrid (SOH) I/Q-modulator for 64 GBd operation
Silicon-organic hybrid (SOH) electro-optic (EO) modulators combine small
footprint with low operating voltage and hence low power dissipation, thus
lending themselves to on-chip integration of large-scale device arrays. Here we
demonstrate an electrical packaging concept that enables high-density
radio-frequency (RF) interfaces between on-chip SOH devices and external
circuits. The concept combines high-resolution
printed-circuit boards with technically simple metal wire bonds and is amenable
to packaging of device arrays with small on-chip bond pad pitches. In a set of
experiments, we characterize the performance of the underlying RF building
blocks and we demonstrate the viability of the overall concept by generation of
high-speed optical communication signals. Achieving line rates (symbols rates)
of 128 Gbit/s (64 GBd) using quadrature-phase-shiftkeying (QPSK) modulation and
of 160 Gbit/s (40 GBd) using 16-state quadrature-amplitudemodulation (16QAM),
we believe that our demonstration represents an important step in bringing SOH
modulators from proof-of-concept experiments to deployment in commercial
environments
RF MEMS ohmic switches for matrix configurations
Two different topologies of radio frequency micro-electro-mechanical system (RF MEMS) series ohmic switches (cantilever and clamped–clamped beams) in coplanar waveguide (CPW) configuration have been characterized by means of DC, environmental, and RF measurements. In particular, on-wafer checks have been followed by RF test after vibration, thermal shocks, and temperature cycles. The devices have been manufactured on high resistivity silicon substrates, as building blocks to be implemented in different single-pole 4-throw (SP4 T), double-pole double-throw (DPDT) configurations, and then integrated in Low Temperature Co-fired Ceramics (LTCC) technology for the realization of large-order Clos 3D networks
Towards fully integrated CMOS RF receivers
The evolution of the mobile telephony is demanding new multi-function terminals (cellular and cordless phones, GPS, pagers) compatible with a variety of standard (GSM, DCS, DECT, CDMA). At the same time the reduction of cost, size and power dissipation is mandatory. All this requires an higher integration level for the RF part, that is presently using a big number of components. This explains the big research effort put in silicon RF circuits particularly in CMOS technology. In this paper the state of the art of CMOS RF circuits is outlined. In particular some results regarding critical building blocks obtained by the STMicroelectronics and Pavia University research team are given. Future evelopments and the progress needed to successfully implement them are also pointed out
Digitally Assisted Adaptive Non-Linearity Suppression Scheme for RF front ends
This paper presents a robust and low-complexity non-linearity suppression scheme for radio frequency (RF) transceiver building blocks to efficiently mitigate intermodulation distortion. The scheme consists of tunable RF components assisted by an auxiliary path equipped with an adaptive digital signal processing algorithm to provide the tuning control. This proposed concept of digitally-assisted tuning is capable of handling a large range of non-linear behaviours without any complexity increase in the expensive RF circuitry and is robust to process, voltage and temperature variations. A case study on the third order intermodulation of the channel select filter for a full 10 MHz Long Term Evolution (LTE) reception bandwidth is used to demonstrate the feasibility and effectiveness of the technique
Spectral Signature Analysis – BIST for RF Front-Ends
In this paper, the Spectral Signature Analysis is presented as a concept for an integrable self-test system (Built-In Self-Test – BIST) for RF front-ends is presented. It is based on modelling the whole RF front-end (transmitter and receiver) on system level, on generating of a Spectral Signature and of evaluating of the Signature Response. Because of using multi-carrier signal as the test signature, the concept is especially useful for tests of linearity and frequency response of front-ends. Due to the presented method of signature response evaluation, this concept can be used for Built-In Self-Correction (BISC) at critical building blocks
Surpassing the classical limit of microwave photonic frequency fading effect by quantum microwave photonics
With energy-time entangled biphoton sources as the optical carrier and
time-correlated single-photon detection for high-speed radio frequency (RF)
signal recovery, the method of quantum microwave photonics (QMWP) has presented
the unprecedented potential of nonlocal RF signal encoding and efficient RF
signal distilling from the dispersion interference associated with ultrashort
pulse carriers. In this letter, its capability in microwave signal processing
and prospective superiority is further demonstrated. Both the QMWP RF phase
shifting and transversal filtering functionality, which are the fundamental
building blocks of microwave signal processing, are realized. Besides the
perfect immunity to the dispersion-induced frequency fading effect associated
with the broadband carrier in classical microwave photonics, a native
two-dimensional parallel microwave signal processor is provided. These
demonstrations fully prove the superiority of QMWP over classical MWP and open
the door to new application fields of MWP involving encrypted processing
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