Analog Signal Processing Circuits Research Articles

A 4-channel Time Interleaved Sampler based 3-5 GHz band CMOS Radar IC in 0.13 mm for Surveillance

This paper presents a 3-5 GHz band CMOS UWB radar IC realized in a 0.13 mm CMOS technology for surveillance. Sampling resolution and detectable range of the proposed IC are determined to be 3 cm and 15 m, respectively, to serve a surveillance function. To reduce the scan time while satisfying resolution and detection range, equivalent time sampling and a 4-channel time interleaved sampler are used. The DC offset mismatch in the 4-channel receiver is greatly reduced via a DC offset compensation and BJT-based op-amp for analog signal processing (ASP) circuits. Measurement results show that the center frequency and bandwidth of the pulse can be adjusted in the range of 3 GHz - 5 GHz and 0.5 GHz - 2 GHz, respectively. The measured range for human target is up to 11 m. The chip size is 4 mm ´ 2.5 mm, and 81 mA (transmitter) and 38 mA (receiver) are consumed at 1.5 V supply.

Chip implementation of supervised neural network using single-transistor synapses

In this work, the newly developed neural chip applied in analog inputs for on-chip training and recognition is presented. We have designed the neural chip using single-transistor synapses which are capable of storing analog weights. The neural chip includes the interface circuit, power switches, analog synaptic array (7 × 4 synapses), and transresistance amplifiers (TR_AMPs) for on-chip training and recognition. Voice signals were acquired using analog signal processing and conditioning circuits for use in verifying the chip's pattern recognition functionality. The experimental results reveal that the synaptic weights of the neural network have adapted with training and have gradually converged to the targets afterwards. Upon system convergence, the recognition rates of the targeted speaker and the three others were evaluated. By using very small amount of synapses, as few as 28 synapses, the system's successful recognition rate for the targeted speaker is 93.5% for 200 tests; whereas, the rate for the other speakers is approximately 6.3% for 600 tests.

Design of Low-Voltage, Low-Power FGMOS Based Voltage Buffer, Analog Inverter and Winner-Take-All Analog Signal Processing Circuits

This paper proposes novel floating-gate MOSFET (FGMOS) based Voltage Buffer, Analog Inverter and Winner-Take-All (WTA) circuits. The proposed circuits have low power dissipation. All proposed circuits are simulated using SPICE in 180 nm CMOS technology with supply voltages of ±1.25 V. The simulation results demonstrate increase in input range for FGMOS based voltage buffer and analog inverter and maximum power dissipation of 0.5 mW, 1.9 mW and 0.429 mW for FGMOS based voltage buffer, analog inverter and WTA circuits, respectively. The proposed circuits are intended to find applications in low voltage, low power consumer electronics.

Detection of Magnetic Material in Soil Subsurface Using Electromagnetic Induction Method Based on Fluxgate Sensor

An instrument based on electromagnetic induction method for detecting magnetic material in soil subsurface has been developed. The instrument consists of a signal generator, an amplifier, a transmitter, receivers, detectors and a display. A coil is used as transmitter. As receiver and also detector is used a three dimensional self-developed fluxgate sensor. The fluxgate sensor consists of two pick-up coils, four excitation coils, and a ferromagnetic core. The output voltage of the sensor is processed using an analog signal processing circuit. The sensor’s capability in detecting magnetic material in the soil subsurface was observed by placing a sample of magnetic material in the subsurface, and then detected using fluxgate sensor in the direction of the x, y and z (3D). We found that the developed instrument is capable to detect two different objects that is separated at minimum distance around 10 cm with the maximum shallow depth of the target material is 10 cm.

Miles A. Copeland: The Analog Maestro

Prof. Miles Copeland?s career spans more than three decades and is marked by the strength of his achievements as an inventor, researcher, mentor, and his remarkable legacy of technologies transferred to local industry. His innovative approach to industry?university collaboration supported the rapid development of the telecommunication and microelectronics industries in Canada between 1968 and 1995. He is the 2016 recipient of the IEEE Donald O. Pederson Award in Solid-State Circuits for his outstanding contributions to the design and application of switched-capacitor, precision-MOS analog, and RF signal processing circuits.

Development of a wireless blood pressure measuring device with smart mobile device

Today, smart mobile devices (telephones and tablets) are very commonly used due to their powerful hardware and useful features. According to an eMarketer report, in 2014 there were 1.76 billion smartphone users (excluding users of tablets) in the world; it is predicted that this number will rise by 15.9% to 2.04 billion in 2015. It is thought that these devices can be used successfully in biomedical applications. A wireless blood pressure measuring device used together with a smart mobile device was developed in this study. By means of an interface developed for smart mobile devices with Android and iOS operating systems, a smart mobile device was used both as an indicator and as a control device. The cuff communicating with this device through Bluetooth was designed to measure blood pressure via the arm. A digital filter was used on the cuff instead of the traditional analog signal processing and filtering circuit. The newly developed blood pressure measuring device was tested on 18 patients and 20 healthy individuals of different ages under a physician's supervision. When the test results were compared with the measurements made using a sphygmomanometer, it was shown that an average 93.52% accuracy in sick individuals and 94.53% accuracy in healthy individuals could be achieved with the new device.

Multifunction Current Differencing Cascaded Transconductance Amplifier (MCDCTA) and Its Application to Current-Mode Multiphase Sinusoidal Oscillator

Abstract In this study, a new versatile active element, namely multifunction current differencing cascaded transconductance amplifier (MCDCTA), is proposed. This device which adopts a simple configuration enjoys the performances of low-voltage, low-input and high-output impedance, wide bandwidth etc. It simplifies the design of the current-mode analog signal processing circuit greatly, especially the design of high-order filter and oscillator circuits. Moreover, an example as a new current-mode multiphase sinusoidal oscillator (MSO) using MCDCTA is described in this paper. The proposed oscillator, which employs only one MCDCTA and minimum grounded passive elements, is easy to be realized. It can provide random n (n being odd or even) output current signals and these output currents are equally spaced in phase all at high output impedance terminals. Its oscillation condition and the oscillation frequency can be adjusted independently, linearly and electronically by controlling the bias currents of MCDCTA. The operation of the proposed oscillator has been testified through PSPICE simulation and experimental results.

Multi-function Current Differencing Cascaded Transconductance Amplifier (MCDCTA) and Its Application to Current-Mode Multiphase Sinusoidal Oscillator

In this study, a new versatile active element, namely multifunction current differencing cascaded transconductance amplifier (MCDCTA) is proposed. The proposed MCDCTA enjoys the advantages of low voltage, low-input and high-output impedance, wide bandwidth etc., and it simplifies the design of the current-mode analog signal processing circuit greatly, especially the design of high-order filter and oscillator circuits. Moreover, an example, a new current-mode multiphase sinusoidal oscillator (MSO) using the proposed MCDCTA is described in this paper. The proposed MSO consists only one MCDCTA and minimum grounded passive elements, it could provide 2n (n ? 2) output current signals with equally phase difference, and the output current signals are all at high output impedance terminals. The oscillation condition and the oscillation frequency of the MSO could be linearly and electronically adjusted by controlling the bias currents of MCDCTA, and it is suitable for variable frequency oscillator application. The operation of the proposed oscillator has been verified through PSPICE simulation and experimental results.

3D 프린팅 방식 유연 촉각센서의 접촉력 측정 알고리즘 개발

Flexible tactile sensors can provide valuable feedback to intelligent robots regarding the environment around them. This is especially important when robots such as, service robots share a workspace with humans. This paper presents a contact force measurement algorithm of a flexible tactile sensor. This sensor is manufactured by a direct-writing technique, which is one 3D printing method, using multi-walled carbon nano-tubes. An analog signal processing circuit has been designed and implemented to reduce noise contained in the sensor output. In addition, a digital version of the Butterworth filter was implemented by software running on a microcontroller. Through various experiments, characteristics of the sensor system have been identified. Based on three traits, an algorithm to detect the contact and measure the contact force has been developed. The entire system showed a promising prospect to detect the contact over a large and curved area.

Low-voltage gate and body driven self-biased cascode current mirror with enhanced bandwidth

In this paper, a new approach to enhance the bandwidth of self-biased cascode current mirror (SBCM) is explored. The proposed approach is based on gate and body driven technique. This technique boosts the transconductance in a MOS transistor as both gate and body/bulk terminals are tied together and used as signal input. This novel technique appears as a good solution to merge the advantages of gate-driven and bulk-driven techniques and suppress their disadvantages. The gate and body driven technique utilise body effect to enable low voltage operation by lowering the threshold voltage of MOS transistor and improves the overall circuit performance. The proposed technique achieves maximum bandwidth extension ratio of about two without compromising DC conditions. The proposed SBCM maintains high current copy accuracy due to improved output resistance and consumes only 131 µW. A small signal analysis validates the advantage of proposed bandwidth extension approach over previously reported approaches. The most attractive feature is design simplicity and complete elimination of any passive component or additional circuitry for bandwidth extension. Simulations in PSpice environment for 180 nm CMOS technology verified the predicted theoretical results. The proposed current mirror is particularly interesting for high frequency low noise analog signal processing and conditioning circuits.

Absolute distance measurement using frequency-sweeping heterodyne interferometer calibrated by an optical frequency comb

We present a frequency-sweeping heterodyne interferometer to measure an absolute distance based on a frequency-tunable diode laser calibrated by an optical frequency comb (OFC) and an interferometric phase measurement system. The laser frequency-sweeping process is calibrated by the OFC within a range of 200 GHz and an accuracy of 1.3 kHz, which brings about a precise temporal synthetic wavelength of 1.499 mm. The interferometric phase measurement system consisting of the analog signal processing circuit and the digital phase meter achieves a phase difference resolution better than 0.1 deg. As the laser frequency is sweeping, the absolute distance can be determined by measuring the phase difference variation of the interference signals. In the laboratory condition, our experimental scheme realizes micrometer accuracy over meter distance.

Development of a signal collecting system for double-channel auscultation

As is known to all, many auscultations of human body, such as heart, lung and carotid artery sound, play a major role in clinic. And their signal frequency is in the range that computer sound card can handle, so we can use analog-to-digital (A/D) conversion of sound card as A/D conversion (ADC) of auscultation signals, and double-channel auscultation signals (DCASs) can be input into personal computer(PC) by sound card that every computer has, and it makes the hardware design more simple. Because auscultation signals are input from sound card, any common music processing software (CMPS) can be used to process received auscultative signals, and it is not necessary to write special processing software for them. Therefore, only a double-channel and front-end analog signal processing circuit of auscultation is needed to be designed. By this method of constituting the signal collecting system for double-channel auscultation, it is simple and low cost, and needs no special software, so it has very important values and a broad market prospect.

Analog Filter Design Using Ring Oscillator Integrators

Integrators are key building blocks in many analog signal processing circuits and systems. The DC gain of conventional opamp-RC or Gm- C integrators is severely limited by the gain of operational transconductance amplifier (OTA) used to implement them. Process scaling reduces transistor output resistance, which further exacerbates this issue. We propose applying ring oscillator integrators (ROIs) in the design of high order analog filters. ROIs implemented with simple CMOS inverters achieve infinite DC gain at low supply voltages independent of transistor non-idealities and imperfections such as finite output impedance. Consequently, ROIs scale more effectively into newer processes. A prototype fourth order filter designed using the ROIs was fabricated in 90 nm CMOS and occupies an area of 0.29 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Operating with a 0.55 V supply, the filter consumes 2.9 mW power and achieves bandwidth of 7 MHz, SNR of 61.4 dB, SFDR of 67.6 dB and THD of 60.1 dB. The measured IM3 obtained by feeding two tones at 1 MHz and 2 MHz is 63.4 dB.

Research on Computer Control System of Automobile Safe Checking Process

According to the national standard GB7258-2004 “The Safety Technology Qualification of the Automobile Run”, the Computer control system of automobile safe checking process we designed can gathers the data of stage meter exactly. It can process and store the data by computer then display and print the result of the examination. This subject mainly emphasizes on the design of the system hardware, mainly include develop a set of stable and dependable analog signal processing circuit and simulation.

Adaptively-biased MOSFET for low voltage CMOS analog circuits

This paper proposes technique for mitigating an issue of “reduced signal voltage range” in existing analog signal processing circuits in finer technologies due to their low supply voltage. The proposed adaptively-biased MOSFET pair can make an MOSFET operate in the saturation or the triode region in a wider voltage range. The simulated results of a source-coupled pair with the proposed structure by using Cadence Spectre and MOSFET parameter of a 0.18 μm CMOS technology are also presented.

Annealing studies on X-ray and neutron irradiated CMOS Monolithic Active Pixel Sensors

Abstract CMOS Monolithic Active Pixel Sensors (MAPS) integrate very small sensing elements with a pitch of 10 – 40 μ m together with analog and digital signal processing circuits into a monolithic chip, which may be thinned down to a thickness of ∼ 50 μ m . These features make MAPS an interesting sensor for a broad range of vertex detectors in charged particle tracking (e.g. CBM, STAR, ILC). Intense R&D was performed in the last years in order to improve the radiation tolerance and hence the lifetime of the sensors toward the level required. One strategy to reach this improvement is reducing the number of metastable, radiation induced defects in the sensor material by thermal annealing. To test the feasibility of this approach, we studied systematically the effect of annealing on neutron and X-ray irradiated MAPS. The results of the studies are presented and the option to recover a strongly irradiated, MAPS based vertex detector by means of thermal treatment is discussed.

Design and implementation of a hybrid circuit system for micro sensor signal processing

This paper covers a micro sensor analog signal processing circuit system (MASPS) chip with low power and a digital signal processing circuit board implementation including hardware connection and software design. Attention has been paid to incorporate the MASPS chip into the digital circuit board. The ultimate aim is to form a hybrid circuit used for mixed-signal processing, which can be applied to a micro sensor flow monitoring system.

A Real-Time Monitoring System Using a Multimodal Sensor with an Electrical Conductivity Sensor and a Temperature Sensor for Cow Health Control

A multimodal sensor composed of an electrical conductivity (EC) sensor and a temperature sensor on the same Si chip was successfully fabricated using compatible complementary metal oxide semiconductor (CMOS) technology. The EC sensor measured the electrical conductivity between Pt electrodes, and the temperature sensor measured the forward voltage of a p–n junction diode. We confirmed the output signal in a wide dynamic range of ECs. For real-time measurement in the rumen of cows, a wireless system was fabricated. The system included a sensor, a battery, an antenna, an analog signal-processing circuit board, an AC-to-DC converter board, and a receiver–transmitter board. We adjusted the wireless system design with focus on the measurement range to adapt the system to the rumen. Real-time and simultaneous measurements of EC and temperature in the rumen using the multimodal sensor unit were performed. The wireless system successfully received signals continuously, and enabled the measurement of the rumen conditions in real time.

Improving the Response of Accelerometers for Automotive Applications by Using LMS Adaptive Filters

In this paper, the least-mean-squares (LMS) algorithm was used to eliminate noise corrupting the important information coming from a piezoresisitive accelerometer for automotive applications. This kind of accelerometer is designed to be easily mounted in hard to reach places on vehicles under test, and they usually feature ranges from 50 to 2,000 g (where is the gravitational acceleration, 9.81 m/s2) and frequency responses to 3,000 Hz or higher, with DC response, durable cables, reliable performance and relatively low cost. However, here we show that the response of the sensor under test had a lot of noise and we carried out the signal processing stage by using both conventional and optimal adaptive filtering. Usually, designers have to build their specific analog and digital signal processing circuits, and this fact increases considerably the cost of the entire sensor system and the results are not always satisfactory, because the relevant signal is sometimes buried in a broad-band noise background where the unwanted information and the relevant signal sometimes share a very similar frequency band. Thus, in order to deal with this problem, here we used the LMS adaptive filtering algorithm and compare it with others based on the kind of filters that are typically used for automotive applications. The experimental results are satisfactory.

High-resolution voltage reference for magnet power supply

This paper presents a high-resolution voltage reference which is suitable for building high-precision magnet power supplies for accelerators. It consists of digital signal processor, field programmable gate array, and two digital-to-analog converter (DAC) boards. The DAC board uses two commercial 16-bit-D/A converters and an analog signal processing circuit to achieve a resolution higher than 20-bit. The proposed voltage reference has a resolution of 20-bit (1 ppm) for the +10 V full scale. The short- and long-term stabilities are ~1 and 5 ppm, respectively. The controllability and reproducibility of the output voltage to a step input were ~1 ppm (10 μV). The equivalent bandwidth of the voltage reference was ~5 kHz. These experimental results show that the proposed voltage reference may be applied to many other systems which require a high-resolution and cost-effective voltage reference with a good long-term stability. The voltage reference can be interfaced with the Ethernet (including EPICS), CAN, and RS232C.