Speed is one of the basic reasons for vehicle accident. Many lives could have been saved if emergency service could get accident information and reach in time. Nowadays, GPS has become an integral part of a vehicle system. This paper proposes to utilize the capability of a GPS receiver to monitor speed of a vehicle and detect accident basing on monitored speed and send accident location to an Alert Service Center. The GPS will monitor speed of a vehicle and compare with the previous speed in every second through a Microcontroller Unit. Whenever the speed will be below the specified speed, it will assume that an accident has occurred. The system will then send the accident location acquired from the GPS along with the time and the speed by utilizing the GSM network. This will help to reach the rescue service in time and save the valuable human life.

The integrated differential ring oscillator (DRO) in complementary metal oxide semiconductor (CMOS) technology has been used in numerous products for a long time. Its presence has been extended to high-speed clock and data recovery (CDR) circuits for optical communication, analog and digitally controlled oscillators, frequency dividers of high-frequency synthesizers, clock generators of digital circuits, analog-to-digital converters (ADCs), and many more applications [1]-[5]. Implementations of these ring oscillators are seen in emerging technologies such as ultrawideband (UWB) and radio frequency identification (RFID) as well as wireless sensor networks (WSNs) and short-range communication devices [6], [7]. The DRO is a good design choice for integrated circuit (IC)designers because of its continued use in different bulk CMOS technologies. This article presents implementation techniques and performance comparisons of the DRO as a CMOS voltage-controlled oscillator (VCO) in low radio frequency (RF) bands, along with presentation and discussion of a number of circuit approaches.

During the last three decades, the remarkable dynamic features of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS), and advances in solid-state electronics hold much potential for the fabrication of extremely sensitive charge sensors. These sensors have a broad range of applications, such as those involving the measurement of ionization radiation, detection of bio-analyte and aerosol particles, mass spectrometry, scanning tunneling microscopy, and quantum computation. Designing charge sensors (also known as charge electrometers) for electrometry is deemed significant because of the sensitivity and resolution issues in the range of micro- and nano-scales. This article reviews the development of state-of-the-art micro- and nano-charge sensors, and discusses their technological challenges for practical implementation.

Fully integrated CMOS single pole double through (SPDT) Transmit/Receive (T/R) switch is an essential component of every compact transceiver for enabling sharing of a single antenna between its transmitter and receiver. The switch is expected to encompass very low insertion loss, relatively higher isolation with high power handling capability. But there is inevitable trade-off among the parameters of the switch which makes the design even more challenging at 2.4 GHz ISM band. This paper presents a bibliographical survey of the work published on improved performance of different switch topologies for 2.4 GHz ISM band transceiver applications. Different techniques reported in literatures for further improvements in the characteristics of CMOS switches are also highlighted. This review will serve as a comparative study and reference for the researchers in designing T/R switches for future 2.4 GHz ISM band applications.

In radio frequency identification (RFID) systems, performance degradation of phase locked loops (PLLs) mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs). This paper proposes a low power, low phase noise ring-VCO developed for 2.42 GHz operated active RFID transponders compatible with IEEE 802.11 b/g, Bluetooth, and Zigbee protocols. For ease of integration and implementation of the module in tiny die area, a novel pseudodifferential delay cell based 3-stage ring oscillator has been introduced to fabricate the ring-VCO. In CMOS technology, 0.18 μm process is adopted for designing the circuit with 1.5 V power supply. The postlayout simulated results show that the proposed oscillator works in the tuning range of 0.5–2.54 GHz and dissipates 2.47 mW of power. It exhibits a phase noise of −126.62 dBc/Hz at 25 MHz offset from 2.42 GHz carrier frequency.

A Low Power 3-Stage Voltage-Controlled Ring Oscillator in 0.18 µm CMOS Process for Active RFID Transponder