便携式信号采集在机器健康诊断系统中有较高的应用价值。机器健康诊断的信号特点是包括低频信号。本文研究是为了实现简易而且低成本的低频便携式信号采集。以Microchip公司单片机PIC18F1320为核心设计信号采集电路，实现了信号的采集和保存。系统采用串行电可擦除芯片24LC32A保存数据，经过有线通信，信号数据由串行口通过MAX232芯片输送到微型计算机接收和保存，最后绘制出信号波形。 微型计算机程序采用Visual Basic编程。研究成功采样频率为3 kHz的复杂信号，证明该方案符合设计要求。 Abstract: Portable signal acquisition is useful in machine health monitoring systems. The signal characteristics of machine health monitoring includes low frequency signals. The goal of this study is to realize simple, inexpensive and portable low frequency signal sampling. This paper provides the project of signal acquisition system design based on PIC18F1320 microcontroller manufactured by the Microchip Technology Incorporation to achieve signal sampling and storage. The system adopted EEPROM 24LC32A to store the signal data. The microcomputer received data via wired link with the MAX232 IC through the serial port. The microcomputer program, programmed in Visual Basic, received the data, stored it and plotted the signal. The study successfully samples 3kHz complicated signals and thus meets the design requirement.
上传时间： 2013-11-19
上传用户：moerwang
Abstract: While many questions still surround the creation and deployment of the smart grid, the need for a reliablecommunications infrastructure is indisputable. Developers of the IEEE 1901.2 standard identified difficult channel conditionscharacteristic of low-frequency powerline communications and implemented an orthogonal frequency division multiplexing (OFDM)architecture using advanced modulation and channel-coding techniques. This strategy helped to ensure a robust communicationsnetwork for the smart grid.
上传时间： 2013-10-18
上传用户：myworkpost
Random Number Generators（随机数生成）包括gaussian random number generator、uniform random number generator、low-frequency hold generator、1/f noise generator等5种随机信号生成的c源代码
标签： generator random number Generators
上传时间： 2014-12-07
上传用户：edisonfather
his project was built and tested with WinAVR-20060125. Make sure the MCU target define in the Makefiles corresponds to the AVR you are using!! To build the code, just install WinAVR and run "make" from the console in echomaster and echoslave subdirs. "make program" will program the device if you have a AVRISP attached. Remember to set the AVR device to at least 8MHz. The AVR may use the programmable clock from MC1319x, just remember to check if the MC1319x and SPI communication is working FIRST! Otherwise you wont get any clock signal to the AVR and then you can t program it or reset the fuses! The MC1319x has default clock output of 32kHz so you will have to set your programmer to a very low frequency (<=32kHz/4) to be able to program it while it is running on that!
标签： the 20060125 project WinAVR
上传时间： 2014-10-10
上传用户：yan2267246
摘要：本系统以ICL8038集成块为核心器件，制作一种函数信号发生器，制作成本较低。适合学生学习电子技术测量使用。ICL8038是一种具有多种波形输出的精密振荡集成电路，只需要个别的外部元件就能产生从0.001Hz~30KlHz的低失真正弦波、三角波、矩形波等脉冲信号。输出波形的频率和占空比还可以由电流或电阻控制。另外由于该芯片具有调制信号输入端，所以可以用来对低频信号进行频率调制。关键词：函数信号发生器频率调制Abstract：The system ICL8038 integrated block as the core device，producing a kind of function signal generator，producing low cost.Suitable for students to learn the use of electronic technology measurement.ICL8038 is a kind of multi-precision oscillator waveform output integrated circuits，a separate external components only need to be able to generate from the 0.001Hz ~30KHz low-distortion sine wave，triangle wave，square wave pulse signal，etc..Output waveform of the frequency and duty cycle can also be controlled by a currentor resistance.In addition，as the chip has a modulated signal input terminal，it can be used to low-frequency signal is frequency modulation.
上传时间： 2022-07-04
上传用户：zhanglei193
Image enhancement in frequency domain using Fourier center frequency, Gaussian lowpass filter, Low pass filter, high pass filter. Image restoration using medean filter, weiner filter with noise generator such as Gaussian noise, Salt and Pepper noise
标签： frequency enhancement Gaussian Fourier
上传时间： 2017-08-24
上传用户：xinzhch
Buffer low THD distortion and hi-impendance, Very wide frequency band.
标签： hi-impendance distortion frequency Buffer
上传时间： 2014-08-08
上传用户：dragonhaixm
The LM158 series consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.
标签： compensated independent internally frequency
上传时间： 2014-01-09
上传用户：zwei41
We address the problem of blind carrier frequency-offset (CFO) estimation in quadrature amplitude modulation, phase-shift keying, and pulse amplitude modulation communications systems.We study the performance of a standard CFO estimate, which consists of first raising the received signal to the Mth power, where M is an integer depending on the type and size of the symbol constellation, and then applying the nonlinear least squares (NLLS) estimation approach. At low signal-to noise ratio (SNR), the NLLS method fails to provide an accurate CFO estimate because of the presence of outliers. In this letter, we derive an approximate closed-form expression for the outlier probability. This enables us to predict the mean-square error (MSE) on CFO estimation for all SNR values. For a given SNR, the new results also give insight into the minimum number of samples required in the CFO estimation procedure, in order to ensure that the MSE on estimation is not significantly affected by the outliers.
标签： frequency-offset estimation quadrature amplitude
上传时间： 2014-01-22
上传用户：牛布牛
The MAX2691 low-noise amplifier (LNA) is designed forGPS L2 applications. Designed in Maxim’s advancedSiGe process, the device achieves high gain andlow noise figure while maximizing the input-referred 1dBcompression point and the 3rd-order intercept point. TheMAX2691 provides a high gain of 17.5dB and sub 1dBnoise figure.
标签： Amplifier Low-Noise 2691 Band
上传时间： 2014-12-04
上传用户：zaocan888
