Receiver Circuit Research Articles

An Approach for Intelligent Traffic Signal Control System for Ambulance Using IoT

Today, many human lives are being expired due to traffic jam and get delayed in reaching the hospital within time. In an emergency condition when a patient is in the ambulance, he/she has to reach the hospital with utmost fast to the nearest hospital should be done in a speedy way to save their lives, hence there is a need to tackle the traffic jam and control the traffic lights accordingly so that ambulance’s lane must be made green and thus providing a stoppage free way for the Ambulance to reach the hospital without delay in time.Normally traffic light systems operate on a timing mechanism that changes the light after a given interval of time. Thus, automated traffic signal releasing system for ambulance will not spend unnecessary time waiting for the traffic lights to change and manage of traffic jam. This proposed project aims to provide facilities and make easier for vehicle in emergency case especially for an ambulance. In an emergency situation, we are using the transmitter and receiver circuit which is using the Radio Frequency (RF) Sensor respectively. The transmitter will send the signal to the receiver that placed at every single traffic light to turn the traffic light from red to green light as the normal traffic is passed through, the traffic light will operate as usual until ambulance vehicle press the button by passing through it. This project aims to design an intelligent traffic light signal which makes the arrival of ambulance free way by halting traffic in case of emergencies. Hence this project will act as a life saver.

Theoretical analysis of the adaptive system for suppression of the interference concentrated on a spectrum

The object of research is the process of interference suppression in a passive radiometric receiver, centered over the interference spectrum, with a random or varying frequency. Noise immunity can be increased by means of special circuits preventing the receiver from overloading and using differences in the characteristics of useful signals and interference to suppress the latter. As a rule, the frequency of noise oscillation is never accurately known and, in addition, the actual interference is never purely harmonic. Therefore, it became necessary to theoretically consider the degree of interference suppression by the input circuit of the radiometer at an unknown value of the interference frequency and the finite width of the spectrum, and also theoretically substantiate possible ways of constructing adaptive devices for suppressing real narrow-band noise. An expression is obtained for the suppression coefficient of the interference concentrated on a spectrum, which shows that the interference will be suppressed automatically for the optimal choice of the parameters k a , τ, T of the servo system. In the paper, a functional diagram of a radiometric receiver is presented, which uses an adaptive system to suppress the spectrum-centered interference. The adaptive system is based on the inclusion in the radiometric receiver circuit of additional compensating circuit interference. The interference compensating circuit makes it possible to increase the sensitivity of the receiver to 10 -20 W with an accuracy of 0.1 oC and a response rate of 2...4 s. In addition to interference suppression, the compensating link after the intermediate frequency amplifier is provided with interference suppression and an input circuit. In this case, the overall amplification in the noise immunity of the radiometric receiver in comparison with the compensating receiver, as calculations for typical characteristics show, will not be worse than 30 dB.

Contactless power transfer system for low power medical devices

Currently, contactless power transfer system is being implemented to power up the medical devices. Those medical devices can either power by transcutaneous cable or batteries. However, the power driven for medical devices via transcutaneous cable might lead to infection due to breach on the skin. The battery replacement surgery for cardiovascular patients also can lead to infection. Therefore, a contactless power transfer system is effectively solving the problem by transmitting power in a safe and non-invasive manner and has mitigate effect to patient health, yet efficient in the power transmission process. Magnetic coupled resonant is being designed since magnetic field cannot be shielded by biological tissues. Resonant power transfer technique can minimize the power scattering on the non-resonant objects such as human body. Impedance matching technique is utilized to improve the overall power transmission efficiency. The system consists a pair of transmitter and receiver coil, transmitter and receiver circuit, and a pair of transformer as impedance matching purpose. The system is capable to achieved a transfer efficiency of over 60%. Contactless power transfer technology does offer the advantages of safety, non-invasive and no significant effect on patient health. Eventually, bacterial infection on the skin breach is prevented.

Ambient Backscatterers Using FM Broadcasting for Low Cost and Low Power Wireless Applications

Nowadays, the explosive growth of Internet-of-Things-related applications has required the design of low-cost and low-power wireless sensors. Although backscatter radio communication is a mature technology used in radio frequency (RF) identification applications, ambient backscattering is a novel approach taking advantage of ambient signals to simplify wireless system topologies to just a sensor node and a receiver (RX) circuit eliminating the need for a dedicated carrier source. This paper introduces a novel wireless tag and RX system that utilizes broadcast frequency modulated (FM) signals for backscatter communication. The proposed proof-of-concept tag comprises of an ultralow-power microcontroller (MCU) and a RF front-end for wireless communication. The MCU can accumulate data from multiple sensors through an analog-to-digital converter, while it transmits the information back to the RX through the front-end by means of backscattering. The front-end uses ON–OFF keying modulation and FM0 encoding on ambient FM station signals. The RX consists of a commercial low-cost software-defined radio which downconverts the received signal to baseband and decodes it using a suitable signal processing algorithm. A theoretical analysis of the error rate performance of the system is provided and compared to bit-error-rate measurements on a fixed transmitter-tag-RX laboratory setup with good agreement. The prototype tag was also tested in a real-time indoor laboratory deployment. Operation over a 5-m tag-reader distance was demonstrated by backscattering information at 2.5 kb/s featuring an energy per packet of $36.9~\mu \text{J}$ .

Three Point Electromagnetic Spider Web

Simple three point electromagnetic spider web combined with the host and the 30 m, 300 m, 3000 m 3 transmitters and 3 receiver circuits, telluric electricity and magnetic switch. Here the space electric field change by using the designed solenoid spider does not need deep inside the earth, a seismometer and earthquake prediction control system is simple. After years of testing, with the use of every minute is four times 5~10 second detection magnetic anomaly, abnormal situation will be asked after the three behind the road before the earthquake electromagnetic parameters is converted to a digital signal electric parameter, if find electromagnetic anomaly in 30 square kilometers will start the GSM switch remote alarm, using Maxwell's equations theory and practice the test showed that this method can not only be used for electromagnetic anomaly before the earthquake prediction, and a plurality of electromagnetic webs can determine epicenter group composition. Before the earthquake changes in the electromagnetic field in a few hours to a few days, be able to know in time that an earthquake is about to occur, and determine the location of the epicenter. The devices may be detected over stealth aircraft. [1-3]

동일대역 전이중 방식 FRS 대역 무전기 개발

In this paper, a self-interference signal cancellation(SIC) circult for In-band Full-Duplex has been developed and tested in RF/analog region. By use of this SIC circuit, a FM two-way radio has been developed working at FRS(Family Radio Service) band. The two-way radio device is transmitting the FM modulated signal and demodulating the wanted FM signal at the same time. A circulator is used to enable a single antenna to transmit and receive simuultaenously. The receiver circuit needs to cancel out the self-interference signal due to the transmit signal. A vector modulator(VM) is used to control the phase and magnitude of the esitmated signal. And in-phase and quadrature correlators are used to figure out the optimal coefficients of the VM to remove the self-interference signal according to the change of channel environment. In this work, SA58646 has been used as the FM transceiver, and the system is tested with a frequency of 465 MHz and a bandwidth of 12.5 kHz FM signal. The output power is 17.2 dBm at the antenna port, and the self intererence signal level is measured −49.2 dBm at the receiver end. Therefore the SIC level is measured by 66.4 dB.

Design of a CMOS ROIC for InGaAs Self-Mixing Detectors Used in FM/cw LADAR

A scannerless laser detection and ranging (LADAR) system based on frequency modulation/continuous wave (FM/cw) technique is attractive due to a reduced bandwidth requirement of the receiver circuit. This paper presents the $64\times 64$ InGaAs-based focal plane array (FPA) self-mixing detectors and the $1\times 32$ element readout integrated circuit (ROIC) array based on transimpedance amplifier for the FM/cw LADAR. Different from conventional detector, the InGaAs self-mixing detector presents a low impedance and a complex electrical model. The linear chirp local-oscillator (LO) electrical signal through the detector causes a large dc current and a unique dc offset voltage (Vos) error in the ROIC. To overcome these problems, the blocking capacitors and the novel multiple low-pass filters are applied in the ROIC. The ROIC array was fabricated in 0.18- $\mu \text{m}$ CMOS process. The measured results show that the Vos error is eliminated within the limited LO amplitude range and the ROIC achieves a 140-dB $\Omega$ transimpedance gain with a bandwidth of 1 MHz. Compared with the state-of-the-art FM/cw LADAR, the ROIC accurately detects the signal of interest of the InGaAs FPA self-mixing detectors and miniaturizes the LADAR receiver.

A Low-Power High-Dynamic-Range Receiver System for In-Probe 3-D Ultrasonic Imaging.

In this paper, a dual-mode low-power, high dynamic-range receiver circuit is designed for the interface with a capacitive micromachined ultrasonic transducer. The proposed ultrasound receiver chip enables the development of an in-probe digital beamforming imaging system. The flexibility of having two operation modes offers a high dynamic range with minimum power sacrifice. A prototype of the chip containing one receive channel, with one variable transimpedance amplifier (TIA) and one analog to digital converter (ADC) circuit is implemented. Combining variable gain TIA functionality with ADC gain settings achieves an enhanced overall high dynamic range, while low power dissipation is maintained. The chip is designed and fabricated in a 65nm standard CMOS process technology. The test chip occupies an area of 76[Formula: see text] 170[Formula: see text]. A total average power range of 60-240[Formula: see text] for a sampling frequency of 30MHz, and a center frequency of 5MHz is measured. An instantaneous dynamic range of 50.5dB with an overall dynamic range of 72dB is obtained from the receiver circuit.

Ambient Light Rejection Using a Novel Average Voltage Tracking in Visible Light Communication System

The quality of a received signal is one of the most important factors to be considered when designing a receiver for visible light communication (VLC) systems. Therefore, it is necessary to evaluate the robustness of the VLC receiver circuit in low-signal-to-noise ratio (SNR) communication. The SNR is the quantity characterized by the ratio of the signal power to the noise power of the received signal. The noise generates an offset voltage and distorts the desired signal waveform. Thus, a low SNR makes it difficult to retrieve the data. Among the sources of noise, ambient light has the most negative impact on the VLC data signal. Therefore, the novel receiver proposed by us acts as an ambient light rejection circuit. As our average-voltage tracking circuit is insensitive to the sunlight and indoor fluorescent light, our design could be a solution to enhance the performance of low-SNR VLC systems. Several experiments are conducted using light of same intensity, but with different distances and semi-angles. Experimental results demonstrate that robust interference rejection is possible to send an error-free communication with an On-Off Keying modulation base on microcontroller up to 1 Mbps at an SNR of −2.7 dB.

Design of full-duplex and multifunction bidirectional CMOS transceiver for optical interconnect applications

This work presents a full-duplex and multifunction bidirectional transceiver for optical interconnect application. The transceiver utilizes a common limiting amplifier/gain stage, thus reducing total chip area and total power consumption. While providing a full-duplex bidirectional transmission with the aid of a hybrid circuit between the electrical input/output (I/O) and the optoelectronic signals from the transmitter and receiver circuits, it also allows for a half-duplex operation with the aid of a switch between the transimpedance amplifier signals and the transmitter electrical input from the I/O port. The multifunction bidirectional CMOS transceiver is designed in a 0.13 µm Si-CMOS technology, with power dissipation of 79 and 54.4 mW for the transmitter and receiver, respectively. It shows a 3-dB bandwidth of 5.58 and 5.69 GHz for the transmitter and the receiver respectively and with a 3-dB gain of 66.14 and 69.6 dB, in full-duplex mode. The transceiver operates up to 7 Gb/s in full-duplex mode.

Multi-level quantization and blind equalization based direct transmission method of digital baseband signal

The direct transmission of digital baseband signals has practical significance in the field of Ethernet terminal connection, high-speed digital communication, data transmission of various types of information peripherals. The signal amplitude gradually decays while the transmission distance increases. Also the attenuation is proportional to the signal frequency, resulting in signal distortion and receiving error. It is a common method for digital baseband signal transmission to use pre-emphasis chip and equalizer chip to improve the transmission quality with a wide range of mature applications. This paper describes a new type of digital signal transmission method, as the receiver using analog-to-digital converter, instead of equalizer chip, to achieve the multi-level quantization of receiving time-domain data waveform. The waveform of the transmitted digital high and low level signal is sampled into multi-bit values. Then, the paper realizes adaptive frequency domain equalization based on soft threshold and makes use of multi-level quantization soft information for error correction. Error correcting code is mainly used to correct the error caused by the channel bandwidth limit, external noise or interference in the process of data transmission, so as to improve the stability and reliability of the transmission. The paper uses the two-stage error correcting codec system based on both Turbo and BCH coding, to achieve the high performance of Turbo code, and good characters of respond time and complexity. The transmitter outputs 12.5 MHz pseudo-random sequence through a 199.93 meter unshielded balanced twisted pair transmission medium. And the receiver circuit using a 62.5MSPS analog-to-digital converter over-samples the waveform to 8-level quantity. The output error of a 65536 bit pseudo-random sequence is less than 8 bits, and the error correction can be further improved by 8b-10b codec. Compared with the traditional pre-emphasis and balanced interface ICs connection, the method described in this article has the advantages of longer transmission distance, better flexibility and wider scope of use.

Power optimisation for wearable heart rate measurement device with wireless charging

Continuous measurement of heart rate is necessary for monitoring the patients with heart ailments. A wearable which continuously measures heart rate of an individual by a method called reflectance-based photoplethysmography (PPG) computes the heart rate of an individual according to the volumetric changes in blood flowing through the body is developed. In order to make the device more compact as well as with IP67 and IP68 standard, wireless charging technique is employed because it helps to get rid of wires while charging. Following the Qi standard for designing wireless power receiver circuits makes the device interoperable and work with greater efficiency with reduced losses. Impedance matching and designing the circuit to operate under resonance condition increases coupling efficiency in case of inductive coupling.

A Wide Dynamic Range CMOS Laser Radar Receiver With a Time-Domain Walk Error Compensation Scheme

This integrated receiver channel designed for a pulsed time-of-flight (TOF) laser rangefinder consists of a fully differential transimpedance amplifier channel and a timing discriminator. The amplitude-dependent timing walk error is compensated by measuring the width and rise time of the received pulse echo and using this information for calibration. The measured bandwidth, transimpedance and minimum detectable signal (SNR ~10) of the receiver channel are 230 MHz, $100~\text {k}\Omega $ and ${\sim } 1~\mu \text {A}$ respectively. The single-shot precision of the receiver is ~3 cm at an SNR of 13 and the measurement accuracy is ±4 mm with compensation within a dynamic range of ~1:100 000. The receiver circuit was realized in a $0.35~\mu \text {m}$ CMOS process and has a power consumption of 150 mW. The functionality of the receiver channel was verified over a temperature range of -20 °C to +50 °C.

Circuits for Optical Based Line of Sight Voice Communication

We present here line of sight communication between a person and his neighbour with the help of optical signal produced by a laser torch which act as a carrier. It is therefore a wireless communication and the transmission can go up to 500 meters. We used photodiode to receive the signal at the receiver. The transmitter circuit comprises condenser microphone transistor amplifier BC547 followed by an op-amp stage built around µA741. When we give a voice signal from the mike, it converts the voice signal into the electrical signal. This electrical signal is fed to IC741 (op-amp) for amplification. The gain of the op-amp can be controlled with the help of 1-mega-ohm potentiometer. The AF output from IC is coupled to the base of a class B amplifier which, in turn, modulates the signal. The transmitter uses 5V power supply. However, the 3-volt laser torch (after removal of its battery) can be directly connected to the circuit-with the body of the torch connected to the class B. The photodiode converts the optical signal into electrical signal and again this signal is amplified using IC741 and a combination of class B push pull amplifiers. The receiver circuit uses an NPN photodiode as the light sensor that is followed by a two-stage transistor preamplifier and IC741 based audio Power amplifier. The receiver does not need any complicated alignment. Just keep the photodiode oriented towards the remote transmitter’s laser point and adjust the volume control for a clear sound. The sensor must not directly face the sun.

QoS-Aware Energy-Efficient Downlink Predictive Scheduler for OFDMA-Based Cellular Devices

We propose a predictive energy-efficient scheduling scheme that optimizes the user equipment (UE)'s bits/joule metric subject to quality-of-service (QoS) constraints in downlink orthogonal frequency-division multiple access (OFDMA) systems. This is achieved by minimizing the number of wake-up transmission time intervals (TTIs), where the UE receiver circuit is on , in a longer time horizon than studied before. The proposed predictive scheduler is supported by a ray-tracing (RT) engine that increases the scheduler's knowledge by long-term information about the users' propagation characteristics. A convex multiobjective binary-integer-programming formulation for the problem is presented to optimize both the UE's energy efficiency (EE) and QoS. The multiobjective formulation is then used for benchmarking of a low-complexity and computationally efficient heuristic scheduler. The results show that the proposed schedulers have significantly improved the UE's EE and the overall capacity of the system, compared with a recently published EE scheduling scheme while maintaining target QoS.

Attojoule Optoelectronics for Low-Energy Information Processing and Communications

Optics offers unique opportunities for reducing energy in information processing and communications while resolving the problem of interconnect bandwidth density inside machines. Such energy dissipation overall is now at environmentally significant levels; the source of that dissipation is progressively shifting from logic operations to interconnect energies. Without the prospect of substantial reduction in energy per bit communicated, we cannot continue the exponential growth of our use of information. The physics of optics and optoelectronics fundamentally addresses both interconnect energy and bandwidth density, and optics may be the only scalable solution to such problems. Here we summarize the corresponding background, status, opportunities, and research directions for optoelectronic technology and novel optics, including sub-femtojoule devices in waveguide and novel 2D array optical systems. We compare different approaches to low-energy optoelectronic output devices and their scaling, including lasers, modulators and LEDs, optical confinement approaches (such as resonators) to enhance effects, and the benefits of different material choices, including 2D materials and other quantum-confined structures. Beyond the elimination of line charging by the use optical connections, the next major interconnect dissipations are in the electronic circuits for receiver amplifiers, timing recovery and multiplexing. We can address these through the integration of photodetectors to reduce or eliminate receiver circuit energies, free-space optics to eliminate the need for timing and multiplexing circuits (while solving bandwidth density problems), and using optics generally to save power by running large synchronous systems. One target concept is interconnects from ~ 1 cm to ~ 10 m that have the same energy (~ 10fJ/bit) and simplicity as local electrical wires on chip.

Charging Time Control of Wireless Power Transfer Systems Without Using Mutual Coupling Information and Wireless Communication System

A charging time control method for wireless power transfer systems with a secondary-side hysteresis output power control is presented. It is a primary-side control method that adopts the combined use of three concepts, namely 1) an intermediate capacitor in the receiver circuit as a power flow indicator, 2) hysteresis switching actions of a shunt decoupling power switch in the receiver circuit to regulate the dc voltage of such intermediate capacitor, and 3) the turn-on and turn-off times of the decoupling switch detected on the primary side for closed-loop control. This method has the advantage of eliminating the need for 1) precise information of the mutual inductance between the transmitter and the receiver coils and 2) wireless communication system for feedback purpose. Practical results obtained from a hardware prototype are included. They confirm the proposed operating principles and indicate that the method can automatically lead to optimal energy efficiency operation.

Three-Point Electromagnetic Spider Web

Simple three-point electromagnetic spider web combined with the host and the 30 m, 300 m, 3000 m 3 transmitters and 3 receiver circuits, telluric electricity and magnetic switch. Here the space electric field change by using the designed solenoid spider does not need deep inside the earth, and a seismometer and earthquake prediction control system is simple. After years of testing, with the use of every minute it is four times 5-10 second detection magnetic anomaly, and abnormal situation will be asked after the three behind the road before the earthquake electromagnetic parameters are converted to a digital signal electric parameter. If finding electromagnetic anomaly in 30 square kilometers will start the GSM switch remote alarm, using Maxwell’s equations theory and practice the test showed that this method can not only be used for electromagnetic anomaly before the earthquake prediction, and a plurality of electromagnetic webs can determine epicenter group composition. Before the earthquake changes in the electromagnetic field in a few hours to a few days, we are able to know in time that an earthquake is about to occur, and determine the location of the epicenter. The devices may be detected over stealth aircraft [1] [2] [3].

A mathematical formulation to design and implementation of a low voltage swing transceiver circuit

On switching a transmitter at gigahertz rate, the data at the receiver's end gets distorted in terms of pulse width and voltage due to line loss and dispersion originating from channel electrical characteristics. Signalling using current sources is an established approach for high frequency applications, but different receiver circuits have been proposed to effectively sense the low voltage swings around some reference voltage, VT. At first, the VT is identified at the receiver's input by a unique method and the corresponding value is found to be 0.822V. Thereafter, a signalling scheme has been proposed to have two different current sources capable of generating a low voltage swing around VT at the receiver's end and at the same time compensating the line loss of the channel. The low voltage swings around VT cause leakage current to increase. The proposed methodology reduces the constant short circuit current due to low voltage swings around VT almost close to 0 from 56μA for 60mV swing. The PVT analyses of the VT determination circuit and the proposed signalling scheme indicate the sensitivity of the proposed approach while operated at 1GHz switching frequency. Further, the crosstalk analysis for a 60mV swing around VT at 180nm CMOS process and single ended point to point drivers portrays that the desired s/h (s is the edge to edge space between two traces and h is the corresponding height from the ground plane) has to be greater than 2.3 for crosstalk noise to be below the critical value. Measurements and simulations also indicate that the proposed methodology for terminated design consumes only 1.08mW for data transfer over point to point interconnects compared to conventional schemes.

A 6-m OOK VLC Link Using CMOS-Compatible p-n Photodiode and Red LED

This letter presents an on – off -keying visible-light-communication (VLC) link realized over 6-m distance. The transmitter is implemented with a commercially available red LED source at 650 nm. While most of the reported high-performance VLC links are using p-insulator-n photodetectors, this receiver employs a simple CMOS-compatible p-n photo-detector. A 150-Mb/s optical wireless transmission is measured with a bit-error rate of $1.3\times 10^{{\mathbf {-6}}}$ , which falls below the forward error correction limit of $3.8\times 10^{{\mathbf {-3}}}$ . The second-order L-C-R equalization is used in both the transmitter and the receiver circuits to achieve maximum bandwidth extension. The VLC link is realized with a low illuminance of 250 lux. This power is below the common indoor illumination levels which enables advanced lighting-compatible VLC applications. The receiver and the source circuits consume around 240 and 105 mW, respectively, which represents to our knowledge a record energy-per-bit level of 2.3 nJ/b.