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<HTML><BODY><PRE></PRE><H2>NAME</H2><PRE> refcof - computes LPC reflection coefficients via various spectrum analysis methods xrefcof- run <EM>refcof</EM> with X Windows interactions and displays</PRE><H2>SYNOPSIS</H2><PRE> <STRONG>refcof</STRONG> [ <STRONG>-P</STRONG> <EM>param</EM> ] [ <STRONG>-p</STRONG> <EM>range</EM> ] [ <STRONG>-r</STRONG> <EM>range</EM> ] [ <STRONG>-l</STRONG> <EM>frame</EM>_<EM>len</EM> ] [ <STRONG>-S</STRONG> <EM>step</EM> ] [ <STRONG>-w</STRONG> <EM>window</EM>_<EM>type</EM> ] [ <STRONG>-m</STRONG> <EM>method</EM> ] [ <STRONG>-o</STRONG> <EM>order</EM> ] [ <STRONG>-e</STRONG> <EM>preemphasis</EM> ] [ <STRONG>-c</STRONG> <EM>conv</EM>_<EM>test</EM> ] [ <STRONG>-i</STRONG> <EM>max</EM>_<EM>iter</EM> ] [ <STRONG>-</STRONG> <STRONG>s</STRONG> <EM>sinc</EM>_<EM>n</EM> ] [ <STRONG>-d</STRONG> ] [ <STRONG>-Z</STRONG> ] [ <STRONG>-z</STRONG> ] [ <STRONG>-x</STRONG> <EM>debug</EM>_<EM>level</EM> ] <EM>file</EM>.<EM>sd</EM> <EM>file</EM>.<EM>rc</EM> <STRONG>xrefcof</STRONG> [ <STRONG>-{rp}</STRONG> <EM>range</EM> ] <EM>sd</EM>_<EM>file</EM></PRE><H2>DESCRIPTION</H2><PRE> <EM>refcof</EM> takes an ESPS sampled data file, <EM>file</EM>.<EM>sd</EM>, and pro- duces an ESPS FEA_ANA analysis file <EM>file</EM>.<EM>rc</EM> containing the reflection coefficients corresponding to one or more fixed- length sampled-data frames. All input frames have the same length <EM>frame</EM>_<EM>len</EM> (see <STRONG>-</STRONG> <STRONG>l</STRONG> option). The initial point of the first frame is determined by the <STRONG>-p</STRONG> option or by <EM>start</EM> in the parameter file. Initial points of any subsequent frames follow at equal intervals <EM>step</EM> (see <STRONG>-S</STRONG> option). Thus the 3 cases <EM>step</EM> < <EM>frame</EM>_<EM>len</EM>, <EM>step</EM> = <EM>frame</EM>_<EM>len</EM>, and <EM>step</EM> > <EM>frame</EM>_<EM>len</EM>, correspond to over- lapping frames, exactly abutted frames, and frames separated by gaps. The number of frames is the minimum sufficient to cover a specified range of <EM>nan</EM> points (see <STRONG>-p</STRONG> and <STRONG>-Z</STRONG> options), given <EM>frame</EM>_<EM>len</EM> and <EM>step</EM>. The last frame in each file may overrun the range, in which case a warning is printed. If a frame overruns the end of a file, it is normally filled out with zeros (but see <STRONG>-Z</STRONG>). The reflection coefficients, along with the computed values for <EM>raw</EM>_<EM>power</EM> and <EM>lpc</EM>_<EM>power</EM>, are then stored in FEA_ANA records. No pitch pulse information is written to the file. If <EM>file</EM>.<EM>sd</EM> is "-" then the input is read from the standard input and if <EM>file</EM>.<EM>rc</EM> is "-" then the output is directed to the standard output. The following spectrum analysis methods are available:9 Autocorrelation Method (AUTOC) - see <STRONG><A HREF="../man3.html/get_auto.3.html">get_auto (3-ESPS)</A></STRONG>9 Covariance Method (COV) - see <STRONG><A HREF="../man3.html/covar.3.html">covar (3-ESPS)</A></STRONG>9 Burg Method (BURG) - see <STRONG><A HREF="../man3.html/get_burg.3.html">get_burg (3-ESPS)</A></STRONG>9 Modified Burg Method (MBURG) - see <STRONG><A HREF="../man3.html/get_burg.3.html">get_burg (3-ESPS)</A></STRONG> <STRONG><A HREF="../man3.html/struct_cov.3.html">struct_cov (3-ESPS)</A></STRONG>, and <STRONG><A HREF="../man3.html/genburg.3.html">genburg (3-ESPS)</A></STRONG>9 Vector Burg Method (VBURG) (fast approximation to structured covariance) - see <STRONG><A HREF="../man3.html/get_vburg.3.html">get_vburg (3-ESPS)</A></STRONG>9 By default, the program uses the autocorrelation method, which applies the standard method of computing the auto- correlation function and the Levinson algorithm for comput- ing the reflection coefficients from the autocorrelation values. Note that the standard autocorrelation method may yield poor results when using a small number (i.e. < 100) of data samples. The other methods can be specified by using the <STRONG>-</STRONG> <STRONG>m</STRONG> option. The most accurate usually is STRCOV, espe- cially for small frame lengths. The methods AUTOC, STRCOV, and STRCOV1 operate by estimating the autocorrelation function and then transforming to reflection coefficients. In these cases, the program can also optionally multiply the autocorrelation function by a sinc function (<STRONG>-s</STRONG> option) prior to computing the reflection coefficients. This has the effect of reducing the spectral resolution if the spectrum of these coefficients is plotted. Of the two structured covariance methods [2], STRCOV is consderably faster and better behaved than STRCOV1. We include STRCOV1 as it may be useful in certain cases. STRCOV uses a fast, single channel algorithm <EM>struct</EM>_<EM>cov</EM> (3- ESPS) developed by John Burg and programmed by Bernard Fraenkel. STRCOV2 uses an older (but more general) algo- rithm <STRONG><A HREF="../man3.html/genburg.3.html">genburg (3-ESPS)</A></STRONG> that was programmed by Daniel Wenger. Note that the <STRONG>-c</STRONG> and <STRONG>-i</STRONG> options are relevant for controlling the convergence of STRCOV. The VBURG method is a fast approximation to structured covariance that was developed and programmed by John Burg and Shankar Narayan [3]. If spectral representations other than reflection coeffi- cients are desired, use <STRONG><A HREF="../man1.html/transpec.1.html">transpec (1-ESPS)</A></STRONG> or <EM>spectrans</EM> (1- ESPS) on the output of <EM>refcof</EM>. If you want the actual spec- trum, use <STRONG><A HREF="../man1.html/me_spec.1.html">me_spec (1-ESPS)</A></STRONG> on the output of <EM>refcof</EM>. <EM>xrefcof</EM> is a script that runs <EM>refcof</EM> on a single frame of data that is specified by the range option (<STRONG>-r</STRONG> or <STRONG>-p</STRONG>) or by means of ESPS Common. A pop-up window is used to prompt the user for <EM>window</EM>_<EM>type</EM>, <EM>method</EM>, <EM>order</EM>, <EM>conv</EM>_<EM>test</EM>, and <EM>max</EM>_<EM>iter</EM>. The results of the <EM>analysis</EM> are displayed in two pop-up windows - one containing the reflection coefficents, and one containing a maximum-entropy power spectrum computed from these reflection coeffiecients. <EM>xrefcof</EM> makes used of <STRONG><A HREF="../man1.html/exprompt.1.html">exprompt (1-ESPS)</A></STRONG>, <STRONG><A HREF="../man1.html/me_spec.1.html">me_spec (1-ESPS)</A></STRONG>, <STRONG><A HREF="../man1.html/plotspec.1.html">plotspec (1-ESPS)</A></STRONG>, and <STRONG><A HREF="../man1.html/xtext.1.html">xtext (1-ESPS)</A></STRONG>. the environment variable ESPS_PARAMS_PATH and put one on that path), it will be used instead.</PRE><H2>OPTIONS</H2><PRE> The following options are supported (only <STRONG>-r</STRONG> or <STRONG>-p</STRONG> can be given for <EM>xrefcof</EM>): <STRONG>-P</STRONG> <EM>param</EM> uses the parameter file <EM>param</EM> rather than the default, which is <EM>params</EM>. <STRONG>-p</STRONG> <EM>first</EM><STRONG>:</STRONG><EM>last</EM> <STRONG>-p</STRONG> <EM>first</EM>-<EM>last</EM> <STRONG>-p</STRONG> <EM>first</EM><STRONG>:+</STRONG><EM>incr</EM> [1:+999] In the first two forms, a pair of unsigned integers specifies the range of sampled data to analyze. If <EM>last</EM> = <EM>first</EM> + <EM>incr</EM>, the third form (with the plus sign) specifies the same range as the first two forms. If <EM>first</EM> is omitted, the default value of 1 is used. If <EM>last</EM> is omitted, then a default frame length of 1000 results. If the specified range contains points not in the file, the last frame is truncated to fit the actual data. Both forms of the option override the values of <EM>start</EM> and <EM>nan</EM> in the parameter file or ESPS Common file. If the <STRONG>-p</STRONG> option is not used, the range is determined from the ESPS Parameter or Common file if the appropriate parameters are present. Note that the default frame length of 1000 also results if <EM>nan</EM> is not in the parameter or Common file and if no <STRONG>-p</STRONG> is used. <STRONG>-r</STRONG> <EM>range</EM> <STRONG>-r</STRONG> is a synonym for <STRONG>-p</STRONG>. <STRONG>-l</STRONG> <EM>frame</EM>_<EM>len</EM> [0] Specifies the length of each frame. If the option is omitted, the parameter file is consulted. A value of 0 (from either the option or the parameter file) indi- cates that a single frame of length <EM>nan</EM> (see <STRONG>-p</STRONG>) is processed; this is also the default value in case <EM>frame</EM>_<EM>len</EM> is not specified either with the <STRONG>-l</STRONG> option or in the parameter file. <STRONG>-S</STRONG> <EM>step</EM> [<EM>frame</EM>_<EM>len</EM>] Initial points of consecutive frames differ by this number of samples. If the option is omitted, the parameter file is consulted, and if no value is found Copyright Entropic Research Laboratory, Inc. 3G3 3 <STRONG>-w</STRONG> <EM>window</EM>_<EM>type</EM>[RECT] The name of the data window to apply to the data in each frame before computing reflection coefficients. If the option is omitted, the parameter file is con- sulted, and if no value is found there, the default used is a rectangular window with amplitude one. Pos- sible window types include rectangular ("RECT"), Ham- ming ("HAMMING"), Hanning ("HANNING"), cosine (COS4), and triangular ("TRIANG"); see the <STRONG><A HREF="../man3.html/window.3.html">window(3-ESPSsp)</A></STRONG> manual page. If the last frame is truncated, the win- dow is applied to the truncated data (e.g., a triangu- lar window is zero at the start and end of the trun- cated data). <STRONG>-m</STRONG> <EM>method</EM>[autoc] Specifies the spectrum analysis method. The default is the autocorrelation method. Also available are the covariance method ("cov"), Burg method ("burg"), modi- fied Burg method ("mburg"), fast modified Burg method ("fburg"), stuctured covariance ("strcov" and "strcov1"), and vector Burg ("vburg", fast approxima- tion to structured covariance. Of the two structured covariance methods, the first ("strcov" is considerably faster and better behaved; "strcov1" is older but included as it may prove useful on occasion. If "strcov" is used, the <STRONG>-c</STRONG> and <STRONG>-i</STRONG> options become relevant. The <STRONG>-m</STRONG> option overrides the value that may be in the parameter file. The default applies only if there is no value in the parameter file. <STRONG>-e</STRONG> <EM>preemphasis</EM>[0.0] Specifies a preemphasis factor to apply to the input signal. <STRONG>-c</STRONG> <EM>conv</EM>_<EM>test</EM>[1e-5] Specifies, for the STRCOV method only (not including STRCOV1), a convergence test value. The lower the value, the smaller the change required on each itera- tion before the estimator terminates, and the more iterations that normally will result. <STRONG>-i</STRONG> <EM>max</EM>_<EM>iter</EM>[20] Specifies, for the STRCOV method only (not including STRCOV1), the maximum number of iterations that the estimator will run through before terminating. A warn- ing will indicate if the estimator terminates because max_iter has been exceeded. Copyright Entropic Research Laboratory, Inc. 4G4 4 no value in the parameter file. <STRONG>-s</STRONG> <EM>sinc</EM>_<EM>n</EM> For the AUTOC, STRCOV, and STRCOV1 methods, the auto- correlation the autocorrelation function is multiplied by the function <EM>sin</EM> (<EM>x</EM> / <EM>sinc</EM>_<EM>n</EM>) before computing the reflection coefficients. In the frequency domain this has the effect of convolving the spectrum with a boxcar function of width <EM>f</EM> / <EM>sinc</EM>_<EM>n</EM>, where <EM>f</EM> is the sampling frequency. The value of <EM>sinc</EM>_<EM>n</EM> is recorded in a gen- eric header item. <STRONG>-d</STRONG> Specifies that the dc component of each frame is removed before the analysis is performed. DC revmoval takes place before windowing. <STRONG>-Z</STRONG> If the last frame normally would overrun the stated range, <EM>refcof</EM> reads past the range to fill up the last frame; if the the last would go past the file end, the frame is filled with zoes. Use of <STRONG>-Z</STRONG>, inhibits this behavior by processing one less frame. The result is that the end of the last frame falls short of the stated range. A common use of <STRONG>-Z</STRONG> is to avoid getting unwanted zeros in training sequences. <STRONG>-z</STRONG> Specifies that /fIrefcof/fP operate silently, without issuing various warnings. <STRONG>-x</STRONG> <EM>debug</EM>_<EM>level</EM> [0] A positive value specifies that debugging output be⌨️ 快捷键说明
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