An Impulse Radio PWM-Based Wireless Data Acquisition Sensor Interface

Abstract

A sensor interface circuit based on impulse radio pulse width modulation (IR-PWM) is presented for low power and high throughput wireless data acquisition systems (wDAQ) with extreme size and power constraints. Two triple-slope analog-to-time converters (ATC) convert two analog signals, each up to 5 MHz in bandwidth, into PWM signals, and an impulse radio (IR) transmitted (Tx) with an all-digital power amplifier (PA) combines them while preserving the timing information by transmitting impulses at the PWM rising and falling edges. On the receiver (Rx) side, an RF-LNA followed by an envelope detector recovers the incoming impulses, and a Tflipflop reverts the impulse sequence back to PWM to be digitized by a time-to-digital converter (TDC). Detailed analysis and design guideline on ATC was introduced, and a proof-of-concept prototype was fabricated for a capacitive micromachined ultrasound transducer (CMUT) imaging system in a 0.18-μm HV CMOS process, occupying 0.18 mm 2 active area and consuming 3.94 mW from a 1.8 V supply. The proposed TDC in this prototype yielded 7-bit resolution, while the entire wDAQ achieved 5.8 effective number of bits (ENOB) at 2 × 10 MS/s.

Passive Wireless Measurement System Based on Wireless Power Transfer Technology

“…where, T and R are the measured values, and T and R are the exact values. Figure 12 shows the error for measured temperature according to Equation (6). Although the error of resistance values in simulations and experiments was large, as shown in Figure 10, the error was less than 1.5%.…”

“…When T 0 = 298.15 K, R 0 = 1000 Ω, and B 0 = 3950. The error in measuring the temperature can be derived from the resistance value, as in Equation (6).…”

“…In the era of rapid development of the Internet of Things (IoT), data acquisition systems have been widely applied in all walks of life [1][2][3], including biomedicine, engineering construction, and industrial manufacturing [4][5][6]. In the process of data acquisition, both information and power need to be transmitted through wires.…”

Microdroplet-Based Organic Vapour Sensor on a Disposable GO-Chitosan Flexible Substrate

“…For that reason, different quasi-digital converters have been reported in literature including resistance-toduty cycle, resistance-to-frequency, and resistance-to period, as they are simpler topologies, offering a wide dynamic range and a simplified interface to digital systems (e.g. microprocessors) [40]- [44].…”

A Highly Robust Interface Circuit for Resistive Sensors

“…This results in large and complex configurations and linearization techniques must be applied due to the intrinsic limitation in the dynamic range [2][3][4]. In contrast, quasi-digital converters, i.e., resistance-to-frequency [5,6], -period [7,8] or -duty-cycle [9] converters, are preferred if the resistance variations are very large. This converters not only provide a wider dynamic range but also simplify interfacing to digital systems, as no analog-to-digital converters (ADCs) are required [10,11].…”