865 research outputs found

    A Low Noise Sub-Sampling PLL in Which Divider Noise Is Eliminated and PD-CP Noise Is not multiplied by N^2

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    This paper presents a 2.2-GHz low jitter sub-sampling based PLL. It uses a phase-detector/charge-pump (PD/CP)that sub-samples the VCO output with the reference clock. In contrast to what happens in a classical PLL, the PD/CP noise is not multiplied by N2 in this sub-sampling PLL, resulting in a low noise contribution from the PD/CP. Moreover, no frequency divider is needed in the locked state and hence divider noise and power can be eliminated. An added frequency locked loop guarantees correct frequency locking without degenerating jitter performance when in lock. The PLL is implemented in a standard 0.18- m CMOS process. It consumes 4.2 mA from a 1.8 V supply and occupies an active area of 0.4 X 0.45 m

    Design of injection locked frequency divider in 65nm CMOS technology for mmW applications

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    In this paper, an Injection Locking Frequency Divider (ILFD) in 65 nm RF CMOS Technology for applications in millimeter-wave (mm-W) band is presented. The proposed circuit achieves 12.69% of locking range without any tuning mechanism and it can cover the entire mm-W band in presence of Process, Voltage and Temperature (PVT) variations by changing the Injection Locking Oscillator (ILO) voltage control. A design methodology flow is proposed for ILFD design and an overview regarding CMOS capabilities and opportunities for mm-W transceiver implementation is also exposed.Postprint (published version

    Divide-by-Three Injection-Locked Frequency Dividers with Direct Forcing Signal

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    Process and Temperature Compensated Wideband Injection Locked Frequency Dividers and their Application to Low-Power 2.4-GHz Frequency Synthesizers

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    There has been a dramatic increase in wireless awareness among the user community in the past five years. The 2.4-GHz Industrial, Scientific and Medical (ISM) band is being used for a diverse range of applications due to the following reasons. It is the only unlicensed band approved worldwide and it offers more bandwidth and supports higher data rates compared to the 915-MHz ISM band. The power consumption of devices utilizing the 2.4-GHz band is much lower compared to the 5.2-GHz ISM band. Protocols like Bluetooth and Zigbee that utilize the 2.4-GHz ISM band are becoming extremely popular. Bluetooth is an economic wireless solution for short range connectivity between PC, cell phones, PDAs, Laptops etc. The Zigbee protocol is a wireless technology that was developed as an open global standard to address the unique needs of low-cost, lowpower, wireless sensor networks. Wireless sensor networks are becoming ubiquitous, especially after the recent terrorist activities. Sensors are employed in strategic locations for real-time environmental monitoring, where they collect and transmit data frequently to a nearby terminal. The devices operating in this band are usually compact and battery powered. To enhance battery life and avoid the cumbersome task of battery replacement, the devices used should consume extremely low power. Also, to meet the growing demands cost and sized has to be kept low which mandates fully monolithic implementation using low cost process. CMOS process is extremely attractive for such applications because of its low cost and the possibility to integrate baseband and high frequency circuits on the same chip. A fully integrated solution is attractive for low power consumption as it avoids the need for power hungry drivers for driving off-chip components. The transceiver is often the most power hungry block in a wireless communication system. The frequency divider (prescaler) and the voltage controlled oscillator in the transmitter’s frequency synthesizer are among the major sources of power consumption. There have been a number of publications in the past few decades on low-power high-performance VCOs. Therefore this work focuses on prescalers. A class of analog frequency dividers called as Injection-Locked Frequency Dividers (ILFD) was introduced in the recent past as low power frequency division. ILFDs can consume an order of magnitude lower power when compared to conventional flip-flop based dividers. However the range of operation frequency also knows as the locking range is limited. ILFDs can be classified as LC based and Ring based. Though LC based are insensitive to process and temperature variation, they cannot be used for the 2.4-GHz ISM band because of the large size of on-chip inductors at these frequencies. This causes a lot of valuable chip area to be wasted. Ring based ILFDs are compact and provide a low power solution but are extremely sensitive to process and temperature variations. Process and temperature variation can cause ring based ILFD to loose lock in the desired operating band. The goal of this work is to make the ring based ILFDs useful for practical applications. Techniques to extend the locking range of the ILFDs are discussed. A novel and simple compensation technique is devised to compensate the ILFD and keep the locking range tight with process and temperature variations. The proposed ILFD is used in a 2.4-GHz frequency synthesizer that is optimized for fractional-N synthesis. Measurement results supporting the theory are provided

    Design of CMOS integrated frequency synthesizers for ultra-wideband wireless communications systems

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    UltraÂŹwide band (UWB) system is a breakthrough in wireless communication, as it provides data rate one order higher than existing ones. This dissertation focuses on the design of CMOS integrated frequency synthesizer and its building blocks used in UWB system. A mixerÂŹbased frequency synthesizer architecture is proposed to satisfy the agile frequency hopping requirement, which is no more than 9.5 ns, three orders faster than conventional phaseÂŹlocked loop (PLL)ÂŹbased synthesizers. Harmonic cancelaÂŹtion technique is extended and applied to suppress the undesired harmonic mixing components. Simulation shows that sidebands at 2.4 GHz and 5 GHz are below 36 dBc from carrier. The frequency synthesizer contains a novel quadrature VCO based on the capacitive source degeneration structure. The QVCO tackles the jeopardous ambiguity of the oscillation frequency in conventional QVCOs. Measurement shows that the 5ÂŹGHz CSDÂŹQVCO in 0.18 ”m CMOS technology draws 5.2 mA current from a 1.2 V power supply. Its phase noise is ÂŹ120 dBc at 3 MHz oïŹ€set. Compared with existing phase shift LC QVCOs, the proposed CSDÂŹQVCO presents better phase noise and power eïŹƒciency. Finally, a novel injection locking frequency divider (ILFD) is presented. ImÂŹplemented with three stages in 0.18 ”m CMOS technology, the ILFD draws 3ÂŹmA current from a 1.8ÂŹV power supply. It achieves multiple large division ratios as 6, 12, and 18 with all locking ranges greater than 1.7 GHz and injection frequency up to 11 GHz. Compared with other published ILFDs, the proposed ILFD achieves the largest division ratio with satisfactory locking range

    Transmitter Architectures Based on Near-Field Direct Antenna Modulation

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    A near-field direct antenna modulation (NFDAM) technique is introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. Near-field direct antenna modulation (NFDAM) can be performed by using either switches or varactors. Two fully-integrated proof-of-concept NFDAM transmitters operating at 60 GHz using switches and varactors are demonstrated in silicon proving the feasibility of this approach

    A Low-Power BFSK/OOK Transmitter for Wireless Sensors

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    In recent years, significant improvements in semiconductor technology have allowed consistent development of wireless chipsets in terms of functionality and form factor. This has opened up a broad range of applications for implantable wireless sensors and telemetry devices in multiple categories, such as military, industrial, and medical uses. The nature of these applications often requires the wireless sensors to be low-weight and energy-efficient to achieve long battery life. Among the various functions of these sensors, the communication block, used to transmit the gathered data, is typically the most power-hungry block. In typical wireless sensor networks, transmission range is below 10 meters and required radiated power is below 1 milliwatt. In such cases, power consumption of the frequency-synthesis circuits prior to the power amplifier of the transmitter becomes significant. Reducing this power consumption is currently the focus of various research endeavors. A popular method of achieving this goal is using a direct-modulation transmitter where the generated carrier is directly modulated with baseband data using simple modulation schemes. Among the different variations of direct-modulation transmitters, transmitters using unlocked digitally-controlled oscillators and transmitters with injection or resonator-locked oscillators are widely investigated because of their simple structure. These transmitters can achieve low-power and stable operation either with the help of recalibration or by sacrificing tuning capability. In contrast, phase-locked-loop-based (PLL) transmitters are less researched. The PLL uses a feedback loop to lock the carrier to a reference frequency with a programmable ratio and thus achieves good frequency stability and convenient tunability. This work focuses on PLL-based transmitters. The initial goal of this work is to reduce the power consumption of the oscillator and frequency divider, the two most power-consuming blocks in a PLL. Novel topologies for these two blocks are proposed which achieve ultra-low-power operation. Along with measured performance, mathematical analysis to derive rule-of-thumb design approaches are presented. Finally, the full transmitter is implemented using these blocks in a 130 nanometer CMOS process and is successfully tested for low-power operation

    Millimeter-wave Communication and Radar Sensing — Opportunities, Challenges, and Solutions

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    With the development of communication and radar sensing technology, people are able to seek for a more convenient life and better experiences. The fifth generation (5G) mobile network provides high speed communication and internet services with a data rate up to several gigabit per second (Gbps). In addition, 5G offers great opportunities of emerging applications, for example, manufacture automation with the help of precise wireless sensing. For future communication and sensing systems, increasing capacity and accuracy is desired, which can be realized at millimeter-wave spectrum from 30 GHz to 300 GHz with several tens of GHz available bandwidth. Wavelength reduces at higher frequency, this implies more compact transceivers and antennas, and high sensing accuracy and imaging resolution. Challenges arise with these application opportunities when it comes to realizing prototype or demonstrators in practice. This thesis proposes some of the solutions addressing such challenges in a laboratory environment.High data rate millimeter-wave transmission experiments have been demonstrated with the help of advanced instrumentations. These demonstrations show the potential of transceiver chipsets. On the other hand, the real-time communication demonstrations are limited to either low modulation order signals or low symbol rate transmissions. The reason for that is the lack of commercially available high-speed analog-to-digital converters (ADCs); therefore, conventional digital synchronization methods are difficult to implement in real-time systems at very high data rates. In this thesis, two synchronous baseband receivers are proposed with carrier recovery subsystems which only require low-speed ADCs [A][B].Besides synchronization, high-frequency signal generation is also a challenge in millimeter-wave communications. The frequency divider is a critical component of a millimeter-wave frequency synthesizer. Having both wide locking range and high working frequencies is a challenge. In this thesis, a tunable delay gated ring oscillator topology is proposed for dual-mode operation and bandwidth extension [C]. Millimeter-wave radar offers advantages for high accuracy sensing. Traditional millimeter-wave radar with frequency-modulated continuous-wave (FMCW), or continuous-wave (CW), all have their disadvantages. Typically, the FMCW radar cannot share the spectrum with other FMCW radars.\ua0 With limited bandwidth, the number of FMCW radars that could coexist in the same area is limited. CW radars have a limited ambiguous distance of a wavelength. In this thesis, a phase-modulated radar with micrometer accuracy is presented [D]. It is applicable in a multi-radar scenario without occupying more bandwidth, and its ambiguous distance is also much larger than the CW radar. Orthogonal frequency-division multiplexing (OFDM) radar has similar properties. However, its traditional fast calculation method, fast Fourier transform (FFT), limits its measurement accuracy. In this thesis, an accuracy enhancement technique is introduced to increase the measurement accuracy up to the micrometer level [E]

    Improve Performance of Adaptive Multi-Modulus Frequency Divider by Pulse Triggered Flip Flop

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    A divider of frequency with minimal power & greater speed with multi modulus is elaborated along design of a PLL. In this document by making use of a ff initiated by a pulse is plowed by which a definite divider with 2 levels can improvise the frequency of function & deduce decadence of power. A constituent which is adaptive s formulated to be retained in a divider with great mode of saving in power. The frequency of a defined divider with 2 levels in accordance to CMOS of 130 nm process may attain 4 GHz. The basic decadence f power is division by 49 mode at 63 uW with frequency of 1 GHz or 156uW at 4 GHz. In a contrast of the counter of Johnson FD, frequency of a divider with 2 levels is improvised & so the proportion of optimization of power

    Ultra high data rate CMOS front ends

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    The availability of numerous mm-wave frequency bands for wireless communication has motivated the exploration of multi-band and multi-mode integrated components and systems in the main stream CMOS technology. This opportunity has faced the RF designer with the transition between schematic and layout. Modeling the performance of circuits after layout and taking into account the parasitic effects resulting from the layout are two issues that are more important and influential at high frequency design. Performing measurements using on-wafer probing at 60 GHz has its own complexities. The very short wave-length of the signals at mm-wave frequencies makes the measurements very sensitive to the effective length and bending of the interfaces. This paper presents different 60 GHz corner blocks, e.g. Low Noise Amplifier, Zero IF mixer, Phase-Locked Loop, a Dual-Mode Mm-Wave Injection-Locked Frequency Divider and an active transformed power amplifiers implemented in CMOS technologies. These results emphasize the feasibility of the realization 60 GHZ integrated components and systems in the main stream CMOS technology
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