New applications such as wireless integrated network sensors (WINS) require radio-frequency transceivers consuming very little power compared to usual mainstream applications, while still working in the ultra-high-frequency range. For this kind of application, the LC-tank-based local oscillator remains a significant contributor to the overall receiver power consumption. This statement motivates the development of good on-chip varactors available in a standard process. This paper describes and compares the available solutions to realize high-Q, highly tunable varactors in a standard digital CMOS submicrometer process. On this basis, quality factors in excess of 100 at 1 GHz, for a tuning ratio reaching two, have been measured using a 0.5-/spl mu/m process.

Design of high-Q varactors for low-power wireless applications using a standard CMOS process

A broad range of high-volume consumer applications require low-power battery-operated wireless microsystems and sensors These systems should conciliate a sufficient battery lifetime with reduced dimensions, low cost, and versatility Their design highlights the tradeoff between performance, lifetime, cost, and power consumption Also, special circuit and design techniques are needed to comply with the reduced supply voltage (down to 1 V, for single battery cell operation) These considerations are illustrated by the design of a prototype receiver chip realized in a standard 05-/spl mu/m digital CMOS process with 06-V threshold voltage The chip is dedicated to a distributed sensors network and is based on a direct-conversion architecture The circuit operates at 1-V power supply in the 434-MHz European ISM band and consumes only 1 mW in receive mode It achieves a -95 dBm sensitivity for a data rate of 24 kb/s

An ultralow-power UHF transceiver integrated in a standard digital CMOS process: architecture and receiver

A method for predicting peripheral nerve damage comprising the steps of placing a pressure transducer on the skin of a patient proximate to a peripheral nerve; measuring the pressure with the pressure transducer over time; and estimating a damage to the nerve based on the pressure and duration of application and a nerve damage model.

System and method for reducing iatrogenic damage to nerves

Key requirements for digital frequency-modulation (FM) demodulators are wide spurious-free dynamic range in the intermediate-frequency quantizer, linear-phase passband filtering, and accurate frequency discrimination. The proposed FM demodulator implemented digitally achieves high linearity by numerical differentiation performed at a 112/spl times/ oversampling rate, suppresses adjacent channels by placing zeros of the SINC function on them, and rejects amplitude-modulation (AM) components by numerical division. A 5-MHz FM demodulator integrated with a fourth-order bandpass delta-sigma front end exhibits 74.7 dB signal-to-noise ratio, -80.7 dB total harmonic distortion, and 61 dB AM rejection within a 9-kHz message bandwidth. The 0.65-/spl mu/m CMOS chip occupies 3.5/spl times/3.5 mm/sup 2/ of active area and consumes 180 mW with 4-V supply when clocked at 20 MHz.

A 5-MHz IF digital FM demodulator

One embodiment of the present invention relates to a communications system. The system includes a Highway-Addressable Remote Transducer (HART) transmitter comprising a direct memory access (DMA) module configured to access at least one transmitter lookup table (LUT) using DMA transfers to modulate a HART data packet into a frequency-shift keying (FSK) data signal. The system also includes a HART receiver configured to demodulate a received FSK data signal into a demodulated HART data packet.

Hart transmitter/receiver systems

A modulator is adapted for use in a transmitter of an information transmission signal in which the information is in the form of a frequency shift keyed code. The signal is centered on a fictional carrier frequency fc, on either side of which are emitted two actual frequencies separated from the frequency fc by Δf, according to whether the binary information has a high value (+1) or a low value (-1). A first generator (1) creates carrier signals in the form of sin(2πf c t) and cos(2πf c t). A second generator (6) creates, as a function of the information, modulation signals of the form sin(2πΔft) and cos(2πΔft) which are mixed with the carrier signals. At each transition of the information, first phase shifting means (8,14) modify by kπ the phase of one of the modulation signals. Second phase shifting means (8,9,10,12), simultaneously with the action of the first phase shifting means and at each transition of the information, change the sign of the argument of the modulation signals. The carrier signal is thus devoid of phase jumps.

Continuous phase frequency shift keying modulator

Low-power single-cell battery-operated fully-featured radio receivers, with a minimum of external components are hard to find. Classical low-voltage heterodyne receivers consisting of bipolar transistor arrays require 50 to 60 external components to realize off-chip selectivity, filtering, demodulation, audio processing, etc. Zero or low intermediate frequency (IF) bipolar integrated circuit (IC) receivers with some on-chip base-band processing circuits require 25 to 40 components, but do not work at 0.9 V or drain more than 10 mA. This BiCMOS receiver IC is a full-featured single-conversion low IF narrow-band FM receiver that needs only 4 to 7 external components. This is made possible by a fully-integrated delay-line FM demodulator using parallelism that enables both automatic-frequency control (AFC) and muting to be realized at IF. Full functionality down to 0.9 V is obtained by ac coupling at radio frequencies (RF) and bulk forward biasing in the CMOS analog and digital building blocks. The receiver uses a BiCMOS process featuring vertical 3.6 /spl mu/m npn and pnp BJTs and 1.2 /spl mu/m 0.86 V V/sub Tmax/ MOS transistors. The chip area is 22 mm/sup 2/.

A 0.9 V 1.2 mA 200 MHz BiCMOS single-chip narrow-band FM receiver

SP 21.5: A 0.9V 1.2mA 200MHz BiCMOS Single-Chip Narrow-Band FM Receiver

This modulator can be used in a transmitter for an information transmission carrier signal in which the information D(t) is coded by frequency shift. The carrier signal is centred on a hypothetical central frequency fc, on either side of which two real frequencies are transmitted, separated from the frequency fc by a frequency Df, according to whether the binary information takes a high (+1) or a low (-1) value. A first generator (1) generates signals, respectively of the form sin(2pfct) and cos(2pfct). A second generator (6), as a function of the information D(t) generates modulation signals I(t) of the form sin(2pDft) and cos(2pDft), these signals being mixed with the carrier signal. The generator (6) comprises first phase-shifting means (8, 14) in order, upon each information transition, to modify, by a value kp, the phase of the modulation signal I(t) and second phase-shifting means (8, 9, 10, 12) in order, simultaneously with the action of the first phase-shifting means and each information transition D(t), to change the sign of the argument of the modulation signals I(t) and Q(t). This results in the carrier signal being free of phase shifts.

Continuous phase modulator

Ce modulateur est utilisable dans un emetteur d'un signal de transmission d'information dans lequel l'information est codee par deplacement de frequence. Ce signal est centre sur une frequence porteuse fictive fc , de part et d'autre de laquelle sont emises deux frequences reelles distantes de la frequence fc de DELTAf, suivant que l'information binaire a une valeur haute (+1) ou basse (-1). Un premier generateur (1) engendre des signaux de la forme sin (2pifc t) et cos (2pifc t). Un deuxieme generateur (6) engendre, en fonction de l'information, des signaux de modulation de la forme sin (2piDELTAft) et cos (2piDELTAft) et melanges au signal porteur. A chaque transition de l'information, des premiers moyens de dephasage (8, 14) modifient de kpi la phase du signal de modulation. Des seconds moyens de dephasage (8, 9, 10, 12) changent simultanement a l'action des premiers moyens de dephasage et a chaque transition de l'information, le signe de l'argument des signaux de modulation. Le signal porteur est ainsi depourvu de sauts de phase.

John F M Gerrits

Papers

Continuous phase frequency shift keying modulator

A 0.9 V 1.2 mA 200 MHz BiCMOS single-chip narrow-band FM receiver

SP 21.5: A 0.9V 1.2mA 200MHz BiCMOS Single-Chip Narrow-Band FM Receiver

Continuous phase modulator

Modulateur de signaux binaires par déplacement de fréquence.