New design of 3.2–4.8 GHz generator for multi-bands architecture of UWB communication

In this paper a new design of Ultra-Wide Band (UWB) generator is presented. This circuit is the most important block in multi-bands transmitter architecture of UWB communication system. The proposed UWB generator is composed of multi-bands voltage controlled oscillator (VCO), mixer and rectangular pulse generator which consist of ring oscillator, time delay and AND gate function. The UWB generator is based on multiplying the rectangular pulse envelope to a continuous sinusoidal wave in order to generate the UWB signal. This UWB generator circuit produces an output signal which is characterized by the bandwidth of 1600 MHz divided into three sub-bands of 528 MHz, centered at frequencies of 3.432, 3.96, 4.488 GHz and the limited Power Spectral Density (PSD) is −41.44 dBm/MHz. The maximum amplitude of UWB signal is 214 mV, the pulse is during of 3 ns and the pulse repetition period (PRP) is 32 ns. The power consumption is approximately equal to 26 mW at a voltage supply of 2.5 V. This topology is designed in CMOS 0.35 μm AMS process technology.     

A fully integrated low power PAM multi-channel UWB transmitter

A new transmitter for ultra-wideband (UWB) impulse radio is described in this paper. The new UWB transmitter implements a low power Gaussian shaping filter to reduce the side-lobe in the frequency domain. A simple pulse amplitude modulation (PAM) circuit is used to keep the power consumption low. The proposed architecture features the simple design, low-power operation, and enables the pulse-shape generation for a multi-channel UWB. The core layout size is only 0.2 mm². The simulation results show that the generated signals satisfy the FCC spectrum mask, and the average power consumption is <1.97 mW for the 1.8 V supply voltage. Pulses are transmitted at a PRF (pulse repetition frequency) of 40.5 MHz in 500 MHz bandwidth channels equally spaced within the 3.1–10.6 GHz UWB. This transmitter is designed and fabricated in a 0.18-μm CMOS process.     

A Fully Differential Digital CMOS UWB Pulse Generator

A new fully digital CMOS pulse generator for impulse radio ultra-wideband (UWB) systems is presented. First, the shape of the pulse which best fits the FCC regulation in the 3.1–5 GHz sub-band of the entire 3.1–10.6 GHz UWB bandwidth is derived and approximated using rectangular digital pulses. In particular, the number and the width of pulses that approximate an ideal template are found through an ad hoc optimization methodology. Then a fully differential digital CMOS circuit that synthesizes the pulse sequence is conceived and its functionality demonstrated through post-layout simulations. The results show a very good agreement with the FCC requirements and a low power consumption.     

Longitudinally Excited CO<Subscript>2</Subscript> Laser with Short Laser Pulse like TEA CO<Subscript>2</Subscript> Laser

We have developed a longitudinally excited CO₂ laser with a short laser pulse similar to that of TEA and Q-switched CO₂ lasers. A capacitor transfer circuit with a low shunt resistance provided rapid discharge and a sharp spike pulse with a short pulse tail. Specifically, a circuit with a resistance of 10 M Ω provided a spike pulse width of 103.3 ns and a pulse tail length of 61.9 μs, whereas a circuit with a shunt resistance of 100 Ω provided a laser pulse with a spike pulse width of 96.3 ns and a pulse tail length of 17.2 μs. The laser pulses from this longitudinally excited CO₂ laser were used for processing a human tooth without carbonization and for glass marking without cracks.      

A 0.8-μW window SAR ADC with offset cancellation for digital DC–DC converters

This letter presents the design of a window successive approximation (SAR) analog-to-digital converter (ADC) using an ultra-fast, offset-cancelled auto-zero comparator for digital DC–DC converters. It is designed in a standard CMOS 0.18 μm process. The ADC has a dynamic reference voltage range to reduce power consumption. The auto-zero scheme of the comparator is realized internally with a preamplifier stage and a latch stage. Post-layout simulation shows that the response time of the comparator from low-to-high and high-to-low is 3.78 ns and 2.47 ns, respectively. The resolution of the proposed window SAR ADC is 7.5 mV. The ADC is fabricated as part of a digital DC–DC converter integrated circuit and measurement results show that an average power consumption of 0.8 μW is achieved. The transient time of the DC–DC converter is within 150 ns for a load current change of 495 mA.     

3–5 GHz FSK-OOK ultra wideband transmitter based on memristive ring oscillator

The compatibility of a memristor with CMOS technology has attracted the attention of many researchers to explore its application further. In this work, an ultra low-power and low-complexity ultra wideband (UWB) chirp transmitter based on memristive ring oscillator (RO) is designed in 0.18 µm TSMC CMOS technology. The Chirp waveform was chosen because of its low side-lobes and large time-bandwidth product, which allows for more spectrum use. OOK and FSK modulation are supported by the proposed UWB chirp transmitter. The chirp frequency is controlled linearly with time across the pulse duration using memristors. The binary data "1" and "0" are encoded using distinct chirp frequencies in FSK TX. The simulation results show a maximum TX output pulse of 457 mV _Vpp with a pulse width of 21 ns. The overall DC power consumption for a pulse repetition frequency (PRF) of 20 MHz is 0.328 mW, equivalent to an energy consumption of 16.4 pJ/pulse. The simulated output amplitude for OOK TX is 453 mV Vpp with a pulse width of 48 ns and a PSD of ? 10 dB over a frequency range of 3.2 to 4.8 GHz. The overall power consumption at 10 MHz PRF is 0.136 mW, which corresponds to an energy consumption of 13.6 pJ/pulse.

     

Analysis and Design of a W-band Coherent Pulsed Transmitter Using a New Timing Scheme

This paper presents the analysis and design of a new W-band pulsed transmitter using injection-locking to achieve pulse-to-pulse coherence and power amplification. First, a new timing scheme is introduced to solve the asynchronous problem that commonly exists in multistage injection-locked transmitters. Then the pulsewidth of one stage in the transmitter is intentionally made somewhat longer than that of the next stage, and thus, the rising edge noise of the output pulse is minimized. Finally, a high coherent peak power can be achieved without using complex power combing techniques. To verify our analysis, a W-band pulse transmitter is designed and fabricated that operates at a 78 ns pulsewidth, 50 μs pulse period, and 600 MHz locking bandwidth. The experiment shows that a coherent peak power of 22.3 ± 0.9 W was achieved at 94.2 GHz.     

1.3μm低功耗光发射模块

本文简述了1.3μm低功耗光发射模块的设计要点、结构特点、主要制作技术及其实测性能。该模块主要用于34Mbit/s以下的单路或双路(业务信号、勤务信号)数字信号的光纤传输系统。出纤功耗≥-20dBm,功耗≤300mW,双路信号调制度5～25％、光上升沿3.5ns。     

A low-noise clockless simultaneous 32-channel wireless neural recording system with adjustable resolution

We present a 32-channel wireless implantable neural recording (WINeR-5) system-on-a-chip (SoC) that operates based on time division multiplexing (TDM) of pulse width modulated (PWM) samples, similar to a single-slope analog to digital converter (ADC) that is made wireless. By transmitting a TDM–PWM signal, we have relaxed the need for wide bandwidth and accurate timing between transmitter and receiver units, which is necessary in wideband digital wireless links. The WINeR-5 system uses FSK modulation scheme with RF carrier at 898/926 MHz. The baseband TDM–PWM signal bandwidth is 18 MHz, which is also the bandwidth of the receiver baseband low-pass filter. Further, by moving the digitization circuitry outside the body, we have reduced the size, complexity, and power consumption of the implantable unit. A clockless asynchronous design has been utilized to manage TDM switching times such that no switching occurs during sensitive PWM onsets. Control over sampling rate, dynamic range, and resolution provides the user with tradeoffs that can optimize the system performance for the intended application. The SoC has been implemented in a 0.5-μm standard CMOS process, measuring 3.3 × 3 mm² and consuming 5.6 mW at ±1.5 V when all channels are active. Measured input referred noise for the entire system, including the receiver at 1 m distance, is 4.9 μV_rms in 1 Hz–8.8 kHz range. Functionality of the WINeR-5 system has also been demonstrated in acute in vivo experiments.     

满足FCC辐射掩模的UWB信号设计算法及性能分析

脉冲波形设计是超宽带无线通信技术研究中的重要内容。以满足联邦通信委员会(FCC)辐射掩模为前提,采用两次迭代的算法逐步对脉冲波形参数进行优化,设计了一种低复杂度、能够最大限度提高UWB系统的辐射功率的UWB信号。同时,研究了经过加性高斯白噪声(AWGN)信道,在跳时扩频脉位调制(TH-PPM)UWB系统中使用该窄脉冲的系统性能。仿真结果表明,该UWB通信系统比通常使用Manchester窄脉冲或Scholtz窄脉冲的UWB系统误码性能更优。这对于UWB系统的实际运用有很好的指导意义。     

An area-power efficient CMOS 4-PAM class AB current-mode pre-emphasis serial link transmitter

This paper presents an area-power efficient CMOS 4-PAM class AB current-mode pre-emphasis transmitter for multi-Gb/s serial links. The proposed transmitter minimizes both chip area and power consumption by constructing pre-emphasis symbols directly from the current symbol, eliminating the need for complex FIR filters and digital-to-analog converters. The differential output current obtained from a class AB pre-amplifier and the push-pull operation of both the current-symbol and pre-emphasis drivers minimizes the electromagnetic interference exerted by channels to neighboring devices. The use of latches at both the multiplexer and pre-amplifier minimizes the effect of power fluctuation and ground bouncing on the output current of the transmitter. The proposed transmitter has been implemented in both UMC-0.13 μm 1.2 V and TSMC-0.18 μm 1.8V CMOS technologies and analyzed using SpectreRF from Cadence Design Systems with BSIM3.3v device models. The effectiveness of the proposed transmitter architecture is validated from the simulation results of both designs.     

Impulse Radio UWB Pulse Shaping for Cognitive Radio Applications

This paper introduces a method of shaping impulse radio Ultra Wideband (UWB) pulses in the context of using higher than normal power transmissions and cognitive radio to provide the ability for such systems to avoid interference with primary users in shared radio spectrum. Using multiple shaping frequencies and a standard Gaussian pulse shape, pulses are shaped in the time domain, according to the requirements of the frequency spectrum in use, and any limits on power spectral density. Simulation results are presented for an example scenario based on measured data, along with a more general approach applicable to a free spectrum scenario. We show that the introduced shaping technique ensures that up to 98.8% of capacity of the UWB bandwidth within the conventional spectrum mask can be achieved for a time scaling factor of 11 ns and shaping frequency of 30 MHz. Capacity well in excess of the 100% achievable with the spectral mask is possible when the transmit power is permitted to increase in areas of ‘white space’ spectrum.     

A 2.4 GHz low power wireless transceiver analog front-end for endoscopy capsule system

This work presents the design and implementation of a 2.4 GHz low power wireless transceiver analog front-end for the endoscopy capsule system in 0.25 μm CMOS. The prototype integrates a low-IF receiver analog front-end (low noise amplifier, double-balanced down-converter, band-pass-filtered AGC loop, and ASK demodulator) and a direct-conversion transmitter analog front-end (20 MHz IF PLL with well-defined amplitude control circuit, ASK modulator, up-converter, and output buffer) on a single chip together with one integrated RF oscillator and two LO buffers. Trade-off has been made over the design boundaries of the different building blocks to optimize the overall system performance. All building blocks feature the circuit topologies that enable comfortable operation at low power consumption. As a result, the IC works at a 2.5 V power supply, while only consuming 15 mW in receiver (RX) mode and 14 mW in transmitter (TX) mode. To build a complete transceiver for the endoscopy capsule system, only an antenna, a duplexer, and a digital controller are needed besides the presented analog front-end chip.     

OTA based on CMOS inverters and application in the design of tunable bandpass filter

A new operational transconductance amplifier (OTA) builds with CMOS inverters only is proposed in this paper. Simulations with typical BSIM3V3 parameters of a 0.35 μm CMOS process have shown a 3.56 GHz gain-bandwidth product under 2.5 V supply voltage. The corresponding total harmonic distortion is equal to 0.46% for 2 V peak–peak differential output voltage. At the same supply voltage, the circuit can provided at each output a voltage swing of 2.25 V peak–peak. From V_DD = 2 V to V_DD = 2.5 V the differential transconductance varies from 72 to 108.4 μΩ⁻¹. The corresponding common mode rejection ratio and the total power consumption are always lower than −31 dBc and 800 μW, respectively. Typical application of a biquad filter is proposed to illustrate the circuit capabilities.     

Rail-to-rail BiCMOS operational amplifier using input signal adapters with floating outputs

An operational amplifier with rail-to-rail input and output voltage range in 0.6 μm BiCMOS technology is presented. Two simple input signal adapters with floating outputs serving as pre-stages are introduced. They are followed by a differential amplifier. The adapters translate the input signals into a floating level within the operating region of the differential amplifier, enabling rail-to-rail operation. An inverter-based simple rail-to-rail class AB output stage has been used. With a single supply of 1.5 V, the proposed rail-to-rail operational amplifier achieves 72 dB DC open-loop gain, 2.54 MHz unity-gain frequency, 62° phase margin, 2.5 V/μs slew rate, and 147 μW power consumption.     

Simple Short-Pulse CO<Subscript>2</Subscript> Laser Excited by Longitudinal Discharge without High-Voltage Switch

We have developed a longitudinally excited CO₂ laser without a high-voltage switch. The laser produces a short laser pulse similar to those from TEA and Q-switched CO₂ lasers. This system, which is the simplest short-pulse CO₂ laser yet constructed, includes a pulsed power supply, a high-speed step-up transformer, a storage capacitor, and a laser tube. At high pressure (4.2 kPa and above), a rapid discharge produces a short laser pulse with a sharp spike pulse. In mixed gas (CO₂: N₂: He = 1: 1: 2) at a pressure of 9.0 kPa, the laser pulse contains a spike pulse of 218 ns and has a pulse tail length of 16.7 μs.     

DC-Coupled Burst-Mode Laser Diode Driver with Automatic Power Control for 1.25Gbit/s PON System

An integrated burst-mode laser diode driver is presented for PON application. The bias current range and modulation current range are 1–75 mA and 5–80 mA respectively. The DC-coupled interface between the driver and the laser diode can tolerate the output transient voltage as low as 0.6v. The novel digital APC loop can stabilize the output average optical power and extinction ratio respectively within ± 0.3 dBm and ± 0.4 dB (−40 to 100^∘C) with less than 0.6 μs initialization time and infinite bias current and modulation current hold time. Moreover, the fast burst response is achieved with burst on/off time less than 5 ns. The chip is implemented in a TSMC 0.35-μm SiGe BiCMOS technology and occupies an area of 1.56 × 1.67 mm² with power consumption of 105 mW from a supply voltage of 2.5 v.     

采样频率和激光脉宽对全波形激光雷达测距精度的影响

全波形激光雷达测距精度,又称测距重复精度或测距标准差,受激光器出光稳定性、激光脉宽、探测器响应时间抖动、电路噪声、波形形态、波形采样频率和波形处理算法等因素影响。理论分析了不同采样频率和不同脉宽对全波形激光雷达测距精度的影响,并采集不同的采样频率(1.25、2.5、5 GHz)和不同脉宽(1、2、3、···、10 ns)条件下的波形数据,经滤波、插值、波形提取等预处理后,利用线性高斯拟合、加权线性高斯拟合、迭代加权线性高斯拟合、期望最大化算法、和Levenberg Marquardt算法共5种算法计算测距值并统计测距精度。实验结果表明,EM算法获得的测距精度相比其他4种算法受到波形畸变的影响最小;加权线性高斯拟合算法获得的测距精度受采样频率变化的影响最小;相同波形幅值条件下,实际脉宽增加2.47倍,利用EM算法获得的测距精度从0.97 mm下降至1.18 mm,因此增加脉宽会降低测距精度;在光脉宽为4 ns的情况下,5 GHz采样频率数据在EM算法获得的测距精度分别为2.5 GHz、1.25 GHz采样频率数据的测距精度的1.71倍和3.07倍,而当2.5 GHz和1.25 GHz采样频率数据分别插值2倍和4倍至5 GHz后,仅为1.17倍和1.29倍,因此提高采样频率能够提高测距精度,而对低采样频率数据进行插值能够获得接近高采样频率数据的测距精度。     

Very short far-infrared pulses from optically pumped CH3OH/D, CH3F, and HCOOH lasers using an EQ-switched CO2laser as a pump source

Very short far-infrared (FIR) pulses were generated from optically pumped CH3F, CH3OH/D, and HCOOH lasers using aQ- switched, current pulsed (200 mA, 100 μs), low pressure (20 torr) CO2laser as a pump source. Values of 20 ns for the rise time and 50 ns for the decay time of the FIR pulses have been observed. The dependence of the FIR pulse shape parameters, i.e., rise time, decay time, and pulse buildup time, on the width of the pump pulse and the pressure of the molecular gas have been investigated experimentally. Due to the regular pulse shape, high repetition rate (350 Hz), high peak power (≳1 W), and broad spectral range (lambda = 100-500 mum), the pulses are very useful for purposes of solid-state and molecular time resolved spectroscopy.     

A low-power,wide-range variable gain CMOS RF transmitter for 900 MHz wireless communications

This paper presents a low-power, wide-range variable gain RF transmitter for 900 MHz-band wireless communication applications based on a standard 0.18 μm CMOS technology. A very wide-range variable gain and high linearity up-conversion mixer is obtained by using a newly transconductance stage. High linearity at low power dissipation driver amplifier can be obtained by adopting a folded cascode topology with an additional gate-source capacitor. The measured results show conversion gain of 16 dB, dB-linear gain variation of 47 dB with the linearity error less than ±0.5 dB, output P-1 dB of 2 dBm, and OIP3 of 12 dBm while dissipating 4 mA from 1.25 V supply.