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Diffstat (limited to 'help/en_US/pmusic.xml')
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1 files changed, 110 insertions, 35 deletions
diff --git a/help/en_US/pmusic.xml b/help/en_US/pmusic.xml index d299b3a..b445409 100644 --- a/help/en_US/pmusic.xml +++ b/help/en_US/pmusic.xml @@ -17,7 +17,7 @@ <refnamediv> <refname>pmusic</refname> - <refpurpose>Psuedospectrum using MUSIC algorithm</refpurpose> + <refpurpose>Computes Psuedospectrum using MUSIC algorithm</refpurpose> </refnamediv> @@ -33,57 +33,132 @@ [S,f] = pmusic(x,p,nfft,fs,nwin,noverlap) [...] = pmusic(...,freqrange) [...,v,e] = pmusic(...) - - Parameters: - x - int|double - vector|matrix - Input signal. In case of a matrix, each row of x represents a + + + + + + </synopsis> +</refsynopsisdiv> + + +<refsection> + <title>Parameters</title> + <variablelist> + <varlistentry><term>x:</term> + <listitem><para> int|double - vector|matrix</para> +<para>Input signal. In case of a matrix, each row of x represents a seperate observation of the signal. If 'corr' flag is specified, then x is the correlation matrix. If w is not specified in the input, it is determined by the algorithm. If x is real valued, then range of w is [0, pi]. - Otherwise, the range of w is [0, 2pi) - p - int|double - scalar|vector - p(1) is the dimension of the signal subspace + Otherwise, the range of w is [0, 2pi)</para> +</listitem></varlistentry> + </variablelist> + +<variablelist> + <varlistentry><term>p:</term> + <listitem><para> int|double - scalar|vector</para> +<para>p(1) is the dimension of the signal subspace p(2), if specified, represents a threshold that is multiplied by - the smallest estimated eigenvalue of the signal's correlation matrix. - w - int|double - vector - w is the vector of normalized frequencies over which the - pseuspectrogram is to be computed. - nfft - int - scalar (Default = 256) - Length of the fft used to compute pseudospectrum. The length of S + the smallest estimated eigenvalue of the signal's correlation matrix.</para> + +</listitem></varlistentry> + </variablelist> + +<variablelist> +<varlistentry><term>w:</term> + <listitem><para> int|double - vector</para> +<para>w is the vector of normalized frequencies over which the + pseuspectrogram is to be computed.</para> + +</listitem></varlistentry> + +</variablelist> + + +<variablelist> +<varlistentry><term>nfft:</term> + <listitem><para> int - scalar (Default = 256)</para> +<para>Length of the fft used to compute pseudospectrum. The length of S (and hence w/f) depends on the type of values in x and nfft. If x is real, length of s is (nfft/2 + 1) {Range of w = [0, pi]} if nfft is even and (nfft+1)/2 {Range of w = [0, pi)} otherwise. - If x is complex, length of s is nfft. - fs - int|double - scalar (Default = 1) - Sampling rate. Used to convert the normalized frequencies (w) to - actual values (f) and vice-versa. - nwin - int|double - scalar (int only)|vector (Default = 2*p(1)) - If nwin is scalar, it is the length of the rectangular window. + If x is complex, length of s is nfft.</para> + +</listitem></varlistentry> + +</variablelist> + +<variablelist> +<varlistentry><term>fs:</term> + <listitem><para> int|double - scalar (Default = 1)</para> +<para>Sampling rate. Used to convert the normalized frequencies (w) to + actual values (f) and vice-versa.</para> + +</listitem></varlistentry> + +</variablelist> + +<variablelist> +<varlistentry><term>nwin:</term> + <listitem><para> int|double - scalar (int only)|vector (Default = 2*p(1))</para> +<para> If nwin is scalar, it is the length of the rectangular window. Otherwise, the vector input is considered as the window coefficients. - Not used if 'corr' flag present. - If x is a vector, windowing not done in nwin in scalar. If x is a - matrix, - noverlap - int - scalar (Default = nwin-1) - number of points by which successive windows overlap. noverlap not - used if x is a matrix - freqrange - string - The range of frequencies over which the pseudospetrogram is + Not used if 'corr' flag present.</para> + +</listitem></varlistentry> + +</variablelist> +<variablelist> +<varlistentry><term>noverlap:</term> + <listitem><para> int - scalar (Default = nwin-1)</para> +<para> number of points by which successive windows overlap. noverlap not + used if x is a matrix</para> + +</listitem></varlistentry> + +</variablelist> +<variablelist> +<varlistentry><term>freqrange:</term> + <listitem><para> string</para> +<para>The range of frequencies over which the pseudospetrogram is computed. Three possible values - 'onesided', 'twosided', 'centered' 'corr' flag Presence indicates that the primary input x is actually a correlation matrix - - Examples: - TODO: - - </synopsis> -</refsynopsisdiv> + </para> + +</listitem></varlistentry> + +</variablelist> +</refsection> + +<refsection> + <title>Description</title> +<para>[S,w] = pmusic(x,p) implements the MUSIC (Multiple Signal Classification) algorithm and returns S, the pseudospectrum estimate of the input signal x, and a vector w of normalized frequencies (in rad/sample) at which the pseudospectrum is evaluated. The pseudospectrum is calculated using estimates of the eigenvectors of a correlation matrix associated with the input data x, where x is specified as either:</para> + + <para> A row or column vector representing one observation of the signal + + </para> +<para>A rectangular array for which each row of x represents a separate observation of the signal (for example, each row is one output of an array of sensors, as in array processing), such that x'*x is an estimate of the correlation matrix</para> +</refsection> + + +<refsection> + <title>Examples</title> + <programlisting role="example"><![CDATA[ + n = 0:199; + x = cos(0.257*%pi*n) + sin(0.2*%pi*n) ; + [S,w]=pmusic(x,2,16,1) + ]]></programlisting> +</refsection> + <refsection> <title>See also</title> <simplelist type="inline"> - <member><link linkend="pburg">| peig | periodogram | pmtm | prony | pwelch | rooteig | rootmusic</link></member> + <member><link linkend="pburg">pburg| peig | periodogram | pmtm | prony | pwelch | rooteig | rootmusic</link></member> </simplelist> </refsection> |