matlab noverlap 参数含义,matlab [B,F.T] = SPECGRAM(A,NFFT,Fs,WINDOW,NOVERLAP)我想知道这个B到...

问题描述：

matlab

[B,F.T] = SPECGRAM(A,NFFT,Fs,WINDOW,NOVERLAP)

我想知道这个B到底是代表什么

直接输SPECGRAM(A,NFFT,Fs,WINDOW,NOVERLAP)是输出语谱图,

下面是help 的结果 ,无奈英语看不懂

SPECGRAM Spectrogram using a Short-Time Fourier Transform (STFT).

B = SPECGRAM(A) calculates the spectrogram for the signal in vector A.

SPECGRAM divides the signal into overlapping segments,windows each

segment and forms the columns of B with their discrete Fourier

transforms.

B = SPECGRAM(A,NFFT,Fs) specifies the number of FFT points used to

calculate the discrete Fourier transforms.If NFFT = [] or is not

specified the default NFFT = minimum of 256 and the length of A.Fs is

the sampling frequency which does not effect the spectrogram but is

used for scaling plots.If Fs=[] or is not specified it defaults to 2

Hz.

B = SPECGRAM(A,NFFT,Fs,WINDOW,NOVERLAP) uses WINDOW to window each

overlapping segment and forms the columns of B with their zero-padded,

length NFFT discrete Fourier transforms.If you specify a scalar for

WINDOW,SPECGRAM uses a Hanning window of length NFFT.WINDOW must

have a length smaller than or equal to NFFT and greater than NOVERLAP.

NOVERLAP is the number of samples each segement of A overlaps.The

default value of NOVERLAP = length(WINDOW)/2.

还有这个B和 用fft函数出来的有什么区别啊

1个回答

分类：

综合

2014-12-16

问题解答：

我来补答

B = SPECGRAM(A)

计算了光谱的信号向量A,SPECGRAM将信号分为重叠部分,窗口部分并且在B列生成离散傅里叶变换.

B = SPECGRAM(A,NFFT,Fs)

指定FFT点的数量来计算离散傅里叶变换.如果NFFT =[]或没有指定默认NFFT=最低的256和向量A的长度：Fs是采样频率不影响谱图但用于缩放绘图.如果Fs=[]或没有指定则默认值为2赫兹.

B = SPECGRAM(A,NFFT,Fs,WINDOW,NOVERLAP)

使用窗口显示窗口重叠部分、补零后的B列、长度NFFT离散傅里叶变换.如果您为窗口指定一个度量,SPECGRAM采用圆形低频滤波器的长度NFFT .窗口必须有一个长度小于或等于NFFT且大于NOVERLAP .NOVERLAP是样品A重叠部分的数量,默认值NOVERLAP=length(WINDOW)/2.

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