低通滤波器

In order to avoid the cumbersome design,the bandpass filter is indierect designed by relationship between it and lowpass filter.

摘 要：为了避开直接设计带通滤波器的繁琐设计步骤要求，利用低通滤波器与带通滤波器的关系，间接设计带通滤波器是创新之处，即通过设计简单的低通滤波器从而达到设计带通滤波器的要求。

The design of digital notch filters can be achieved through three steps:firstly,the design of analog lowpass filter; secondly,it is analog lowpass to analog band stop filter conversion;at last,using the bilinear transformation make the analog notch filters change into digital notch filters.

研究一种在Matlab语言环境下设计IIR数字陷波滤波器的方法，在数字陷波滤波器设计过程中，先进行模拟低通滤波器的设计，然后进行模拟低通/模拟带阻滤波器转换，最后采用双线性变化法将模拟陷波滤波器转化成数字陷波滤波器。

along with the development of digital technology,digital filters are widely used in many fields,this paper introduces how to design a iir digital notch filters in matlab environment.the design of digital notch filters can be achieved through three steps:firstly,the design of analog lowpass filter; secondly,it is analog lowpass to analog band stop filter conversion;at last,using the bilinear transformation make the analog notch filters change into digital notch filters.the paper also introduces how to design the transfer function of the digital notch filters using all the zeros and farthest points at the same time,it also introduces the program of the digital notch filters under butterworth analog lowpass prototype.

摘 要：随着数字技术的发展，数字滤波器在许多领域得到广泛的应用。研究一种在matlab语言环境下设计iir数字陷波滤波器的方法，在数字陷波滤波器设计过程中，先进行模拟低通滤波器的设计，然后进行模拟低通/模拟带阻滤波器转换，最后采用双线性变化法将模拟陷波滤波器转化成数字陷波滤波器。提出一种用所有零点和极点来表达数字陷波器传递函数的方法，同时给出以巴特沃斯模拟低通为原型设计数字陷波滤波器的程序。关键词：无限冲激响应；巴特沃斯滤波器；数字陷波滤波器；matlab；双线性变换

To solve the problems of the limescale ,the oxidation which are produced by the direct contact between a metallic conductor and water, the detecting reliability and the service life, the utility model adopts the technical proposal as below: the proposal comprises a monostable controllable trigger, a second low-pass filter, a voltage follower and a display circuit, the power circuit links with the monostable controllable trigger, the second low-pass filter, the display circuit and a timebse pulse circuit separately, the utility model is characterized in that the monostable controllable trigger, the second low-pass filter and the display circuit sequentially links, the monstable controllable trigger separately links with a water lever sensor and the timebase pulse circuit.

为了解决金属导体与水直接接触会产生水垢和氧化，影响检测可靠性和使用寿命的问题，本实用新型采用了以下技术解决方案：它包括单稳可控触发器，二阶低通滤波器，电压跟随器和显示电路，电源电路分别与单稳触发器，二阶低通滤波器，显示电路和时基脉冲电路相接，其特征在于单稳可控触发器，二阶低通滤波器，电压跟随器和显示电路依次相接，单稳可控触发器分别与水位传感器和时基脉冲电路相接。

To solve the problems of the limescale ,the oxidation which are produced by the direct contact between a metallic conductor and water, the detectingreliability and the service life, the utility model adopts the technical proposal as below: the proposal comprises a monostable controllable trigger, a second low-pass filter, a voltage follower and a display circuit, the power circuit links with the monostable controllable trigger, the second low-passfilter, the display circuit and a timebse pulse circuit separately, the utility model is characterized in that the monostable controllable trigger, the second low-pass filter and the display circuit sequentially links, the monstable controllable trigger separately links with a water lever sensor and thetimebase pulse circuit.

为了解决金属导体与水直接接触会产生水垢和氧化、影响检测可靠性和使用寿命的问题，本实用新型采用了以下技术解决方案：它包括单稳可控触发器、二阶低通滤波器、电压跟随器和显示电路，电源电路分别与单稳触发器、二阶低通滤波器、显示电路和时基脉冲电路相接，其特征在于单稳可控触发器、二阶低通滤波器、电压跟随器和显示电路依次相接，单稳可控触发器分别与水位传感器和时基脉冲电路相接。

An optimal filter is designed specially for dq transform used in the voltage mea-surement of transfer switch,which is composed of lower-order notch filter and lower-order low pass filter with higher cut-off frequency in series.Its transfer function is presented by theoretical derivation.If the order is same,it is better in measuring the positive sequence of fundamental amplitude than the average filter and the low-pass filter.

针对转换开关电压检测法——dq变换设计了优化滤波器，该滤波器是利用低阶陷波滤波器和较高截止频率低阶低通滤波器串联形成的，通过理论推导给出了该滤波器的传递函数，在相同的滤波阶数下，该优化数字滤波器在提取基波正序幅值的性能比较中，优于平均值滤波法及低通数字滤波器法等。

THD+N: 20-Hz HPF, 20-kHz AES17 LPF Dynamic range: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Signal-to-noise ratio: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Channel separation: 20-Hz HPF, 20-kHz AES17 LPF Analog performance specifications are measured using the System Twot Cascade audio measurement system by Audio Precision in the averaging mode.

的THD + N：20 Hz的高通滤波器，20千赫AES17 LPF的动态范围：20 Hz的高通滤波器，20千赫AES17低通滤波器，A加权信号噪音比：20 Hz的高通滤波器，20 kHz的AES17，A加权频道分离低通滤波器：20 Hz的高通滤波器，20千赫AES17 LPF的模拟性能指标均采用了精密音频系统Twot梯级音频测量系统中的平均模式。

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The invention discloses a construction method of biorthogonal wavelet, which is based on Bernstein base and comprises the following steps that:(1) a lowpass filter at a discomposing and reconstructing end is expressed by Bernstein base;(2) numerical calculation of the lowpass filter is carried out;(3) the lowpass filter at the discomposing and reconstructing end is led to meet the conditions to reconstruct the lowpass filter entirely;(4) the parameter of obtained biorthogonal wavelet is calculated.

本发明公开了一种基于Bernstein基的双正交小波构造方法，包括如下步骤：(1)将分解与重构端的低通滤波器用Bernstein基来表示；(2)进行低通滤波器的数值计算；(3)使分解与重构端的滤波器满足完全重构滤波器的条件；(4)计算获得双正交小波的参数。

With low pass filter use Bessel for least amount of overshoot in the time domain, and Cauer for fastest roll off in the freq domain.

在时域，最小超调量的低通滤波器用Bessel滤波器，在频率域是滚降最快速的低通滤波器用Cauer 或elliptic滤波器。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。