Main Content

designVarSlopeFilter

Design variable slope lowpass or highpass IIR filter

全部收缩in page

句法GydF4y2Ba

[[b，，，，一个] = designVarSlopeFilter(slope,Fc)
[[b，，，，一个] = designVarSlopeFilter(slope,Fc,type)
[[b，，，，一个] = designVarSlopeFilter(___GydF4y2Ba，，，，名称，价值）GydF4y2Ba

Description

例子GydF4y2Ba

[[GydF4y2BabGydF4y2Ba，，，，GydF4y2Ba一个GydF4y2Ba] = designVarSlopeFilter(slope，，，，GydF4y2BaFCGydF4y2Ba）GydF4y2Badesigns a lowpass filter with the specified slope and cutoff frequency.bGydF4y2Baand一个GydF4y2Ba矩阵的分子和分母coeffici吗ents, with columns corresponding to cascaded second-order sections (SOS).

例子GydF4y2Ba

[[GydF4y2BabGydF4y2Ba，，，，GydF4y2Ba一个GydF4y2Ba] = designVarSlopeFilter(slope，，，，GydF4y2BaFCGydF4y2Ba，，，，GydF4y2Batype）GydF4y2Baspecifies the design type as a lowpass or highpass filter.

[[GydF4y2BabGydF4y2Ba，，，，GydF4y2Ba一个GydF4y2Ba] = designVarSlopeFilter(___GydF4y2Ba，，，，GydF4y2Ba名称，价值GydF4y2Ba）GydF4y2Baspecifies options using one or more名称，价值GydF4y2Bapair arguments.

Examples

全部收缩GydF4y2Ba

Open Live Script

Design two second-order section (SOS) lowpass IIR filters usingdesignVarSlopeFilter。GydF4y2Ba

Specify the sampling frequency, slope, and normalized cutoff frequency for two lowpass IIR filters. The sampling frequency is in Hz. The slope is in dB/octave.

FS = 48E3;坡度= 18;FC1 = 10E3/（FS/2）;fc2 = 16e3/（fs/2）;GydF4y2Ba

Design the filter coefficients using the specified parameters.

[B1，A1] = DesignVarslopeFilter（斜率，FC1，GydF4y2Ba"Orientation"，，，，GydF4y2Ba"row"）；[[b2,A2] = designVarSlopeFilter(slope,Fc2,"Orientation"，，，，GydF4y2Ba"row"）；GydF4y2Ba

可视化您的过滤器设计。GydF4y2Ba

fvt = fvtool([B1,A1],[B2,A2],Fs=Fs,FrequencyScale="log"）；legend(fvt,"Fc = 10 kHz"，，，，GydF4y2Ba"Fc = 16 kHz"，位置=GydF4y2Ba"southwest"）GydF4y2Ba

图量响应（DB）包含一个轴对象。带有标题幅度响应（DB）的轴对象包含2个类型线的对象。这些对象表示FC = 10 kHz，FC = 16 kHz。GydF4y2Ba

Open Live Script

使用使用二阶截面（SOS）LowPass IIR过滤器使用GydF4y2BadesignVarSlopeFilter。使用低通滤波器处理音频信号。GydF4y2Ba

Create audio file reader and audio device writer objects. Use the sample rate of the reader as the sample rate of the writer.

框架= 256;filereader = dsp.audiofilereader（GydF4y2Ba。。。GydF4y2Ba“ Rockguitar-16-44p1-Stereo-72secs.wav”GydF4y2Ba，，，，GydF4y2Ba。。。GydF4y2BaSampleSperFrame = frameSize）;采样= filereader.mamplater;DeviceWriter = AudioDeviceWriter（GydF4y2Ba。。。GydF4y2Ba采样=采样）;GydF4y2Ba

通过设备播放音频信号。GydF4y2Ba

count = 0;whilecount < 2500 audio = fileReader(); deviceWriter(audio); count = count + 1;结尾GydF4y2Ba重置（fileReader）GydF4y2Ba

设计具有12 dB/八度斜率和0.15归一化截止频率的低通滤波器。GydF4y2Ba

slope = 12; cutoff = 0.15; [B,A] = designVarSlopeFilter(slope,cutoff);

可视化您的过滤器设计。To output filter coefficients suitable for弗雷克斯GydF4y2Ba， 称呼GydF4y2BadesignVarSlopeFilteragain with the same design specifications but with方向GydF4y2Ba调成GydF4y2Ba"row"。GydF4y2Ba

[[bvisualize,Avisualize] = designVarSlopeFilter(slope,cutoff,Orientation="row"）；[h，f] = freqz（[bvisalize avisalize]，[]，采样）;图（f/1000，mag2db（abs（h）））网格ylim（[-75 5]）xlabel（GydF4y2Ba“频率（kHz）”GydF4y2Ba）ylabel("Magnitude Response (dB)"）GydF4y2Ba

图包含一个轴对象。轴对象包含一个类型行的对象。GydF4y2Ba

创建一个双quad过滤器。GydF4y2Ba

myFilter = dsp.BiquadFilter(。。。GydF4y2Basosmatrixsource =GydF4y2Ba"Input port"，，，，GydF4y2Ba。。。GydF4y2BaScaleValuesInputPort=false);

Create a spectrum analyzer to visualize the original audio signal and the audio signal passed through your lowpass filter.

范围= dsp.spectrumanalyaler（GydF4y2Ba。。。GydF4y2Ba采样=采样，GydF4y2Ba。。。GydF4y2BaPlotAsTwoSidedSpectrum=false,。。。GydF4y2Ba频率计算=GydF4y2Ba"Log"，，，，GydF4y2Ba。。。GydF4y2Ba频率解决方案=GydF4y2Ba"WindowLength"，，，，GydF4y2Ba。。。GydF4y2BaWindowLength=frameSize,。。。GydF4y2Ba标题=GydF4y2Ba“原始和均衡信号”GydF4y2Ba，，，，GydF4y2Ba。。。GydF4y2Bashowlegend = true，GydF4y2Ba。。。GydF4y2BaChannelNames = {GydF4y2Ba'Original Signal'，，，，GydF4y2Ba'Filtered Signal'});

Play the filtered audio signal and visualize the original and filtered spectrums.

count = 0;whilecount < 2500 originalSignal = fileReader(); filteredSignal = myFilter(originalSignal,B,A); scope([originalSignal(:,1),filteredSignal(:,1)]); deviceWriter(filteredSignal); count = count + 1;结尾GydF4y2Ba

一个s a best practice, release your objects once done.

释放（DeviceWriter）版本（fileReader）release(scope)

Figure Spectrum Analyzer contains an axes object and other objects of type uiflowcontainer, uimenu, uitoolbar. The axes object with title Original and Equalized Signal contains 2 objects of type line. These objects represent Original Signal, Filtered Signal.

Open Live Script

Design two second-order section (SOS) highpass IIR filters usingdesignVarSlopeFilter。GydF4y2Ba

Specify the sampling frequency in Hz, the slope in dB/octave, and the normalized cutoff frequency.

FS = 48E3;斜率1 = 18;Slope2 = 36;FC = 4000/（FS/2）;GydF4y2Ba

Design the filter coefficients using the specified parameters.

[B1，A1] = DesignVarslopeFilter（Slope1，FC，GydF4y2Ba"hi"，，，，GydF4y2Ba"Orientation"，，，，GydF4y2Ba"row"）；[[b2,A2] = designVarSlopeFilter(slope2,Fc,"hi"，，，，GydF4y2Ba"Orientation"，，，，GydF4y2Ba"row"）；GydF4y2Ba

可视化您的过滤器设计。GydF4y2Ba

fvt = fvtool([B1,A1],[B2,A2],。。。GydF4y2Ba“ FS”GydF4y2Ba，fs，GydF4y2Ba。。。GydF4y2Ba"FrequencyScale"，，，，GydF4y2Ba"Log"）；legend(fvt,“斜率= 18 dB/八度”GydF4y2Ba，，，，GydF4y2Ba。。。GydF4y2Ba"slope = 36 dB/octave"，，，，GydF4y2Ba。。。GydF4y2Ba“地点”GydF4y2Ba，，，，GydF4y2Ba"NorthWest"）GydF4y2Ba

图量响应（DB）包含一个轴对象。带有标题幅度响应（DB）的轴对象包含2个类型线的对象。这些对象表示斜率= 18 dB/八度，斜率= 36 dB/八度。GydF4y2Ba

Open Live Script

Plosives are consonant sounds resulting from a sudden release of airflow. They are most pronounced in words beginning withpGydF4y2Ba，，，，GydF4y2BadGydF4y2Ba，，，，andGGydF4y2Ba听起来。可以通过录制过程来强调plosives，并且通常会令人不快。在此示例中，您可以通过应用高通滤波和低频压缩来最大程度地减少语音信号的质量。GydF4y2Ba

Create adsp.audiofilereaderGydF4y2Baobject and aAudioDeviceWriterGydF4y2Ba对象从文件中读取音频信号并将音频信号写入设备。播放未加工的信号。然后发布文件读取器和设备编写器。GydF4y2Ba

filereader = dsp.audiofilereader（GydF4y2Ba'audioPlosives.wav'）；DeviceWriter = AudioDeviceWriter（GydF4y2Ba'SampleRate'，fileReader.mamplater）;GydF4y2Bawhile〜ISDONE（FILEREADER）AUDIOIN = FILEREADER（）;DeviceWriter（Audioin）;GydF4y2Ba结尾GydF4y2Ba释放（DeviceWriter）版本（fileReader）GydF4y2Ba

设计一个高通滤波器，其陡峭的降低了120 Hz以下的所有频率。用一个GydF4y2Badsp.BiquadFilterobject to implement the highpass filter design. Create a crossover filter with one crossover at 250 Hz. The crossover filter enables you to separate the band of interest for processing. Create a dynamic range compressor to compress the dynamic range of plosive sounds. To apply no make-up gain, set theMakeupgainmodeGydF4y2Bato "财产”GydF4y2Baand use the default 0 dB化妆GydF4y2Baproperty value. Create a time scope to visualize the processed and unprocessed audio signal.

[[b，，，，一个] = designVarSlopeFilter(48,120/(fileReader.SampleRate/2),"hi"）；biquadFilter = dsp.BiquadFilter(。。。GydF4y2Ba"SOSMatrixSource"，，，，GydF4y2Ba"Input port"，，，，GydF4y2Ba。。。GydF4y2Ba"ScaleValuesInputPort"，，，，false); crossFilt = crossoverFilter(。。。GydF4y2Ba"SampleRate"，，，，fileReader.SampleRate,。。。GydF4y2Ba"NumCrossovers"，，，，1,。。。GydF4y2Ba“交叉频率”GydF4y2Ba，，，，250,。。。GydF4y2Ba"CrossoverSlopes"，，，，48); dRCompressor = compressor(。。。GydF4y2Ba"Threshold"，，，，-35,。。。GydF4y2Ba“比率”GydF4y2Ba，，，，10,。。。GydF4y2Ba"KneeWidth"，，，，20,。。。GydF4y2Ba“攻击时间”GydF4y2Ba，，，，1e-4,。。。GydF4y2Ba“推出日期”GydF4y2Ba，3E-1，GydF4y2Ba。。。GydF4y2Ba"MakeUpGainMode"，，，，GydF4y2Ba“财产”GydF4y2Ba，，，，GydF4y2Ba。。。GydF4y2Ba"SampleRate"，fileReader.mamplater）;范围= timescope（GydF4y2Ba。。。GydF4y2Ba"SampleRate"，，，，fileReader.SampleRate,。。。GydF4y2Ba"TimeSpanSource"，，，，GydF4y2Ba"property"，，，，GydF4y2Ba"TimeSpan"，，，，3,。。。GydF4y2Ba"BufferLength"，fileReader.mamplater*3*2，GydF4y2Ba。。。GydF4y2Ba"YLimits"，[-1 1]，GydF4y2Ba。。。GydF4y2Ba“ showgrid”GydF4y2Ba，，，，true,。。。GydF4y2Ba“ Showlegend”GydF4y2Ba，，，，true,。。。GydF4y2Ba“频道名称”GydF4y2Ba，，，，{'Original'，，，，GydF4y2Ba'处理'GydF4y2Ba});

In an audio stream loop:

  1. Read in a frame of the audio file.

  2. 使用双向过滤器应用高通滤波。GydF4y2Ba

  3. 将音频信号分为两个频段。GydF4y2Ba

  4. 一个pply dynamic range compression to the lower band.

  5. Remix the channels.

  6. Write the processed audio signal to your audio device for listening.

  7. 在时间范围内可视化处理和未经处理的信号。GydF4y2Ba

一个s a best practice, release your objects once done.

while〜ISDONE（FILEREADER）AUDIOIN = FILEREADER（）;Audioin = Biquadfilter（Audioin，b，a）;[band1，band2] = crossfilt（audioin）;band1 compressed = dRCompressor（band1）;AudioOut = band1compressed + band2;DeviceWriter（AudioOut）;范围（[Audioin AudioOut]）GydF4y2Ba结尾GydF4y2Ba

一个s a best practice, release your objects once done.

释放（DeviceWriter）版本（fileReader）release(crossFilt) release(dRCompressor) release(scope)

输入参数GydF4y2Ba

全部收缩GydF4y2Ba

Filter slope in dB/octave, specified as a real scalar in the range [0:6:48]. Values that are not multiples of 6 are rounded.

Data Types:single|GydF4y2Badouble|GydF4y2Baint8|GydF4y2Baint16|GydF4y2Baint32|GydF4y2Baint64|GydF4y2Bauint8|GydF4y2Bauint16|GydF4y2Bauint32|GydF4y2Bauint64

Normalized cutoff frequency, specified as a real scalar in the range 0 to 1, where 1 corresponds to the Nyquist frequency (π rad/sample).

Data Types:single|GydF4y2Badouble|GydF4y2Baint8|GydF4y2Baint16|GydF4y2Baint32|GydF4y2Baint64|GydF4y2Bauint8|GydF4y2Bauint16|GydF4y2Bauint32|GydF4y2Bauint64

过滤类型，指定为GydF4y2Ba'lo'GydF4y2Baor'hi'。GydF4y2Ba

  • 'lo'GydF4y2Ba–– Lowpass filter

  • 'hi'–– Highpass filter

Data Types:char|GydF4y2Bastring

名称值参数GydF4y2Ba

Specify optional pairs of arguments asName1=Value1,...,NameN=ValueN，，，，whereName是参数名称和GydF4y2BaValueis the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

before R2021a, use commas to separate each name and value, and encloseNamein quotes.

Example:'定向'，“行”GydF4y2Ba

方向of returned filter coefficients, specified as the comma-separated pair consisting of'Orientation'and"column"or"row"：GydF4y2Ba

Data Types:char|GydF4y2Bastring

Output Arguments

全部收缩GydF4y2Ba

分子滤波器系数，作为矩阵返回。大小和解释GydF4y2BabGydF4y2Ba取决于GydF4y2Ba方向GydF4y2Ba：GydF4y2Ba

  • 如果GydF4y2Ba'Orientation'is set to"column"， 然后GydF4y2BabGydF4y2Ba作为3 x-4矩阵返回。每一列GydF4y2BabGydF4y2Bacorresponds to the numerator coefficients of a different second-order section of your cascaded IIR filter.

  • 如果GydF4y2Ba'Orientation'is set to"row"， 然后GydF4y2BabGydF4y2Bais returned as a 4-by-3 matrix. Each row ofbGydF4y2Bacorresponds to the numerator coefficients of a different second-order section of your cascaded IIR filter.

Denominator filter coefficients, returned as a matrix. The size and interpretation of一个GydF4y2Ba取决于GydF4y2Ba方向GydF4y2Ba：GydF4y2Ba

  • 如果GydF4y2Ba'Orientation'is set to"column"， 然后GydF4y2Ba一个GydF4y2Ba作为2 x-4矩阵返回。每一列GydF4y2Ba一个GydF4y2Ba对应于级联IIR过滤器的不同二阶部分的分母系数。GydF4y2Ba一个GydF4y2Ba不包括每个部分的领先统一系数。GydF4y2Ba

  • 如果GydF4y2Ba'Orientation'is set to"row"， 然后GydF4y2BabGydF4y2Bais returned as a 4-by-3 matrix. Each row ofbGydF4y2Ba对应于级联IIR过滤器的不同二阶部分的分母系数。GydF4y2Ba

References

[1] Orfanidis，Sophocles J.“高阶数字参数均衡器设计。”GydF4y2BaJournal of the Audio Engineering Society.Vol. 53, November 2005, pp. 1026–1046.

Extended Capabilities

C/C++ Code Generation
使用MATLAB®CODER™生成C和C ++代码。GydF4y2Ba

版本历史记录GydF4y2Ba

在R2016a中引入GydF4y2Ba

也可以看看GydF4y2Ba

|GydF4y2Ba|GydF4y2Ba

话题GydF4y2Ba