Jubayer Jalil

CMOS Differential Ring Oscillators: Review of the Performance of CMOS ROs in Communication Systems

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.

Accident detection and reporting system using GPS, GPRS and GSM technology

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.

Designing a ring-VCO for RFID transponders in 0.18 μm CMOS process.

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.

Design of a novel adder-less Barker matched filter for RFID

Radio frequency identification RFID is the utilization of the radio frequency for the purpose of identification. RFID is lagging behind due to vendor specific solutions and excessive implementation cost. A Wireless Fidelity WiFi compatible IEEE 802.11 RFID tag can overcome these limitations. IEEE 802.11 utilizes Direct Sequence Spread Spectrum DSSS technique and a matched filter is a vital block in a DSSS system. A low-power and low-area novel adder-less Barker matched filter is proposed in this paper by eliminating the conventional multiple multiplications. The matched filter designed in 0.18µm CMOS technology achieves average and maximum power consumption of 33.747µW and 8.08mW, respectively and chip area of 0.41184mm2 only. The simulation result shows the correct matching of data against the threshold value. Compared with the conventional matched filter, the design achieves 25% power reduction maximum power and 51% chip area reduction. Therefore, the design will help to implement a low-power matched filter for IEEE 801.11 compatible RFID tag. Copyright

Differential ring oscillator based voltage control oscillator for readerless RFID transponder

Designing a compact, power efficient voltage controlled oscillator (VCO) for high frequency phase lock loop (PLL) in modern wireless communication system is decisively a challenging task. Inappropriately designed VCOs for battery-powered radio frequency identification (RFID) transponder cause huge degradation of overall system. The proposed work presents a low power 2.45 GHz VCO developed for active readerless transponder compatible with IEEE 802.11b protocol. A 3-stage, single delay path, differential ring oscillator based architecture has been adopted for the ease of integration and implementation of the circuit in small die area. 0.18μm CMOS process is used for designing the proposed VCO. Simulated results showed that the proposed VCO would work in the tuning range of 2.4GHz-2.5GHz with 1.8V supply. Thus, the proposed VCO will be a key component for readerless RFID transponder.