696 research outputs found
Demodulating AM square signals via a digital timer for sensor applications
This paper evaluates theoretically and
experimentally the performance of a timer-based demodulator
applied to low-frequency amplitude-modulated (AM) square
signals coming from sensor circuits. The demodulator extracts
the amplitude of the AM square signal by measuring the period
of a reference triangular signal that is altered by the AM signal
itself, as already suggested in a previous paper but for AM
sinusoidal signals.Postprint (published version
A long-range and long-life telemetry data-acquisition system for heart rate and multiple body temperatures from free-ranging animals
The system includes an implantable transmitter, external receiver-retransmitter collar, and a microprocessor-controlled demodulator. The size of the implant is suitable for animals with body weights of a few kilograms or more; further size reduction of the implant is possible. The ECG is sensed by electrodes designed for internal telemetry and to reduce movement artifacts. The R-wave characteristics are then specifically selected to trigger a short radio frequency pulse. Temperatures are sensed at desired locations by thermistors and then, based on a heartbeat counter, transmitted intermittently via pulse interval modulation. This modulation scheme includes first and last calibration intervals for a reference by ratios with the temperature intervals to achieve good accuracy even over long periods. Pulse duration and pulse sequencing are used to discriminate between heart rate and temperature pulses as well as RF interference
The floating capacitor as a differential building block
This paper analyzes the advantages and limitations of using the floating- (or flying-) capacitor technique as a building block with differential input and either differential or single-ended output to implement voltage amplifiers, multiplexers,
and coherent amplitude demodulators. Theoretical analysis, supported by experimental results, shows that the fully differential configuration has a better common-mode rejection ratio (CMRR). However, if the output signal, once amplified, must be
single ended, then it may be better to have a floating capacitor with single-ended output in amplifiers and some multiplexers
whereas in demodulators a floating capacitor with differential output yields a better CMRR.Peer Reviewe
Realization of OFCC based transimpedance mode instrumentation amplifier
The paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three Operational Floating Current Conveyors (OFCCs) and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA) is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematicThe paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three operational floating current conveyors (OFCCs) and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA) is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematic
Preliminary candidate advanced avionics system for general aviation
An integrated avionics system design was carried out to the level which indicates subsystem function, and the methods of overall system integration. Sufficient detail was included to allow identification of possible system component technologies, and to perform reliability, modularity, maintainability, cost, and risk analysis upon the system design. Retrofit to older aircraft, availability of this system to the single engine two place aircraft, was considered
Magnetic sensors and gradiometers for detection of objects
Disertační práce popisuje vývoj nových detekčních zařízení s anizotropními magnetorezistoryThis thesis describes development of innovative sensor systems based on anisotropi
A remote biological data acquisition system
http://www.worldcat.org/oclc/692968
CMOS low voltage preamplifier based on 1/F noise cancellation
Noise in CMOS integrated circuits -- Noise sources in MOSFET transistors- -- Low noise techniques -- Chopper stabilization technique -- A CHS behavior model in MATLAB/SIMULINK -- Supplemental analysis of CHS -- Low voltage operation & elementary circuits -- Voltage requirements of analog circuits -- Basic circuits and functions -- Implementation of the CHS modules -- Noise in cascaded stages -- Modulators -- Selective amplifier -- Automatic tuning & machine oscillator -- Simulation results and experimental prototype
- …