Pembangkitan Pulsa Orde Nanodetik Berbasis Mikrokontroler Untuk Eksitasi Transduser Ultrasonik

ABSTRAK Makalah ini melaporkan suatu teknik pembangkitan pulsa lebar orde nanodetik (ns) repetitif yang terprogram berbasis mikrokontroler untuk keperluan eksitasi transduser ultrasonik. Pembangkitan pulsa dan pengaturan jarak antar pulsa dilakukan melalui operasi timer mikrokontroler. Sebuah monostable multivibrator mengubah lebar pulsa dari mikrokontroler dalam orde nanodetik melalui pengaturan komponen pewaktuan resistor-kapasitor (RC) dengan cara pengaturan nilai R yang dibuat dari sebuah potensiometer digital. Hasil pengujian menunjukkan bahwa mikrokontroler membangkitkan pulsa repetitif dengan interval terprogram dalam orde 1 detik dan lebar pulsa minimum 1,25 ms. monostable multivibrator dapat mengubah lebar pulsa tersebut menjadi sekitar 140 ns. Berdasarkan hasil pengujian, dapat disimpulkan bahwa sistem berfungsi sesuai rancangan, sistem dapat membangkitkan pulsa repetitif dengan lebar pulsa hingga 140 ns dengan parameter interval dan lebar yang dapat diprogram. Kata kunci: generator pulsa, lebar pulsa singkat, mikrokontroler, monostable multivibrator, eksitasi transduser ultrasonik ABSTRACT This paper reports a repetitive, programmable, microcontroller-based pulse width generation technique for the purpose of ultrasonic transducer excitation. Pulse generation and distance adjustment between pulses is done through the microcontroller timer. A monostable multivibrator changes the pulse width of the microcontroller in the order of nanoseconds by adjusting the resistor-capacitor time constant which are done by adjusting the R value made from a digital potentiometer. The test results show that the microcontroller generates repetitive pulses with programmed intervals in order of 1 second and pulse width of 1.25 ms. A monostable multivibrator converts the pulse width to ca. 140 ns. Based on the test results, it can be concluded that the system functions according to the design as the system can generate repetitive pulses with pulse widths up to 140 nanoseconds with programmable interval and width parameters. Keywords: pulse generator, short-width pulse, microcontroller, monostable multivibrator, ultrasonic transducer excitation

An energy efficient time-mode digit classification neural network implementation

This paper presents the design of an ultra-low energy neural network that uses time-mode signal processing). Handwritten digit classification using a single-layer artificial neural network (ANN) with a Softmin-based activation function is described as an implementation example. To realize time-mode operation, the presented design makes use of monostable multivibrator-based multiplying analogue-to-time converters, fixed-width pulse generators and basic digital gates. The time-mode digit classification ANN was designed in a standard CMOS 0.18 μm IC process and operates from a supply voltage of 0.6 V. The system operates on the MNIST database of handwritten digits with quantized neuron weights and has a classification accuracy of 88%, which is typical for single-layer ANNs, while dissipating 65.74 pJ per classification with a speed of 2.37 k classifications per second. This article is part of the theme issue ‘Harmonizing energy-autonomous computing and intelligence’.

An On-Chip Digital Monostable Multivibrator Using Inverter-based Delay Chains

Monostable multivibrator or one-shot timer is widely used in signal processing. In this paper, a simple and useful way to realize retriggerable monostable multivibrator by using digital logic gates is presented. The basic circuit is composed of one D flip-flop, one NAND gate, one inverter (INV) and two inverter-based delay chains. The width of the output pulse is adjusted through tuning the delay of the inverter-based delay chain. The retriggerable characteristic is realized by resetting all the delayed signals when new triggering occurs in the current monostable period. The basic circuit is designed and fabricated on-chip using a 180[Formula: see text]nm standard CMOS process with effective area less than 1200[Formula: see text][Formula: see text]m2. The retriggerable version is realized in a FPGA platform. Both simulated and measured results are in agreement with the theoretical analysis.

Dual-Mode Controlled Pulse Width Monostable Multivibrator Using DVCCs

This paper proposes a dual-mode controlled pulse width monostable multivibrator used for analogue signal processing applications that employs two differential voltage current conveyors (DVCCs), four passive components and an analogue switch. Unlike the traditional operational-amplifier-based monostable multivibrators, the proposed circuit contributes a dual-mode controlled scheme for adjusting the output pulse width through a voltage source and a grounded resistor. This paper discusses several previous designs and presents the circuit operations, related governing formulas, non-ideal effect problems, design considerations, and experimental examples of the proposed circuit. A prototype circuit was implemented, and commercially integrated circuits and discrete passive components were used to execute the experimental tests. The features of the proposed circuit are discussed, and the experimental results indicated that the circuit is feasibly used in dual-mode controlled pulse width for the output pulse and were consistent with those of the theoretical analyses.

A NOVEL CURRENT-TUNABLE MONOSTABLE MULTIVIBRATOR USING SINGLE DISO-OTA

This paper proposes a novel monostable multivibrator featuring compact topology and current-tunable property. The proposed circuit was composed of a single differential input single output operational transconductance amplifier (DISO-OTA) with a few passive components. It was operated by a negative-edge triggering signal to generate an output pulse. The pulse height and width were tunable by the bias current of DISO-OTA and the external resistors. The proposed scheme is more compact than the existing topologies. This paper presents the circuit operations and a discussion of the non-ideal issues and design considerations. To demonstrate the feasibility of the proposed circuit, a prototype circuit built with commercially available DISO-OTA IC was used to execute the experimental tests. Is-Spice simulation and experimental results were consistent with theoretical analysis.