This is a device for use by RC hobbysts: it transforms a servo from proportional to integrative. For RC boats, it allows user not to change the functionality of the throttle stick, UP/DOWN in stead of proportional. The archive contains also the PCB files.
I. C. Wong, Z. Shen, J. G. Andrews, and B. L. Evans, ``A Low Complexity Algorithm for proportional Resource Allocation in OFDMA Systems , Proc. IEEE Int. Work. Signal Processing Systems, 針對(duì)這篇文章給出的源代碼
Abstract: Quartz crystals are mechanical resonators with piezoelectric properties. The piezoelectricproperties (electric potential across the crystal is proportional to mechanical deformation) allow their use
Sensors for pressure, load, temperature, acceleration andmany other physical quantities often take the form of aWheatstone bridge. These sensors can be extremely linearand stable over time and temperature. However, mostthings in nature are only linear if you don’t bend them toomuch. In the case of a load cell, Hooke’s law states that thestrain in a material is proportional to the applied stress—as long as the stress is nowhere near the material’s yieldpoint (the “point of no return” where the material ispermanently deformed).
鎖定放大是微弱信號(hào)檢測(cè)的重要手段。基于相關(guān)檢測(cè)理論，利用開關(guān)電容的開關(guān)實(shí)現(xiàn)鎖定放大器中乘法器的功能，提出開關(guān)電容和積分器相結(jié)合以實(shí)現(xiàn)相關(guān)檢測(cè)的方法，并設(shè)計(jì)出一種鎖定放大器。該鎖定放大器將微弱信號(hào)轉(zhuǎn)化為與之相關(guān)的方波，通過后續(xù)電路得到正比于被測(cè)信號(hào)的直流電平，為后續(xù)采集處理提供方便。測(cè)量數(shù)據(jù)表明鎖定放大器前級(jí)可將10-6 A的電流轉(zhuǎn)換為10-1 V的電壓，后級(jí)通過帶通濾波器級(jí)聯(lián)可將信號(hào)放大1×105倍。該方法在降低噪聲的同時(shí)，可對(duì)微弱信號(hào)進(jìn)行放大，線性度較高、穩(wěn)定性較好。
Abstract:
Lock-in Amplifying（LIA）is one of important means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
he LPC932 can be used to create a Pulse Width Modulated PWM signal. That s an analog signal, with only 2 discrete levels, for example 0V and 5V and a constant period. The current value of this signal at a certain poiTnt of time is proportional to its Duty Cycle. That s the High Time during one period divided by the period. It can also be calculated as the average value during a particular period. That means after low pass filtering, (e.g. RC circuit) the signal becomes analog, with an actual value controlled by the microcontroller. The PWM functionality enables the LPC932 to control for example the speed of DC motors or the brightness of electric lighting.
This software is developed to provide ease with controller design. For PID control, options are given
to design and analyse the compensated and uncompensated system. You are free to choice among proportional
PI, PD and PID mode of control. Both frequency and time domain characteristics can be observed. Special
Menus are given to observe time and frequency response plots. For Statefeedback controller similar options
are given. But this is limited to second order system only.
本應(yīng)用筆記介紹一種采用dsPIC數(shù)字信號(hào)控制器（Digital Signal Controller，DSC）或PIC24單片機(jī)來實(shí)現(xiàn)無刷直流（Brushless Direct Current，BLDC）電機(jī)無傳感器控制的算法。該算法利用對(duì)反電動(dòng)勢(shì)（Back-Electromotive Force，BEMF）進(jìn)行數(shù)字濾波的擇多函數(shù)來實(shí)現(xiàn)。通過對(duì)電機(jī)的每一相進(jìn)行濾波來確定電機(jī)驅(qū)動(dòng)電壓換相的時(shí)刻。這一控制技術(shù)省卻了分立的低通濾波硬件和片外比較器。需指出，這里論述的所有內(nèi)容及應(yīng)用軟件，都是假定使用三相電機(jī)。該電機(jī)控制算法包括四個(gè)主要部分：·利用DSC或單片機(jī)的模數(shù)轉(zhuǎn)換器（Analog-to-Digital Converter，ADC）來采樣梯形波BEMF信號(hào)·PWM導(dǎo)通側(cè)ADC采樣，以降低噪聲并解決低電感問題·將梯形波BEMF信號(hào)與VBUS/2進(jìn)行比較，以檢測(cè)過零點(diǎn)·用擇多函數(shù)濾波器對(duì)比較結(jié)果信號(hào)進(jìn)行濾波·以三種不同模式對(duì)電機(jī)驅(qū)動(dòng)電壓進(jìn)行換相：-傳統(tǒng)開環(huán)控制器·傳統(tǒng)閉環(huán)控制器比例-積分（proportional-Integral，Pl）閉環(huán)控制器
