cat

speech signal process tools

LPCANA(1-ESPS)                              ENTROPIC RESEARCH LAB



NNNNAAAAMMMMEEEE
     lpcana  -  Performs  LPC  analysis  using  a  crude   pitch-
     synchronous method

SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
     llllppppccccaaaannnnaaaa [ ----PPPP _p_a_r_a_m__f_i_l_e ] [ ----rrrr _r_a_n_g_e ] [ ----pppp  rrrraaaannnnggggeeee ]  [   ---- mmmm
     _a_n_a_l__m_e_t_h_o_d ] [ ----FFFF ] [ ----xxxx _d_e_b_u_g__l_e_v_e_l ] _i_n_p_u_t__s_d _o_u_t_p_u_t__f_e_a

DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     Use of this program is not recommended.  For pitch  synchro-
     nous  analysis,  see  _e_p_o_c_h_s  (1 -ESPS) and _p_s__a_n_a (1-ESPS).
     _l_p_c_a_n_a takes as input an ESPS sampled data FEA_SD (5 - ESPS)
     file and it computes LPC filter coefficients and the excita-
     tion parameters using a crude pitch-synchronous method.  The
     results  are stored in the FEA_ANA (5-ESPS) file _o_u_t_p_u_t__f_e_a.
     For each analysis frame of data, _l_p_c_a_n_a generates reflection
     coefficients,  power,  and  voicing  information.  An output
     FEA_ANA record is generated for each pulse  (several  pulses
     per  analysis  frame),  with  enough  information  to enable
     _l_p_c_s_y_n_t (1-ESPS) to re-synthesize speech.  The nominal frame
     size  is  set  by the parameter _l_p_c__f_r_a_m_e__s_i_z_e but is deter-
     mined adaptively by the program.  If the ----FFFF  option  is  not
     used,  _r_e_f_c_o_f  performs  an  additional spectral analysis on
     each pulse within the analysis frame and  puts  out  a  dif-
     ferent  set of reflection coefficients for each pulse (if ----FFFF
     is used, all pulses from the same analysis  frame  have  the
     same reflection coefficients).

     If "-" is used in place of _i_n_p_u_t__s_d, standard input is used.
     If  " - " is used in place of _o_u_t_p_u_t__f_e_a, standard output is
     used.

OOOOPPPPTTTTIIIIOOOONNNNSSSS
     The following options are supported:

     ----PPPP _p_a_r_a_m__f_i_l_e
          uses the parameter  file  _p_a_r_a_m__f_i_l_e  rather  than  the
          default file _p_a_r_a_m_s.

     ----pppp _r_a_n_g_e
          Selects a subrange of points to be analyzed. The  start
          and end points are defined with respect to the original
          SD file that is the source of the input  FEA_ANA  file.
          The  range  is  specified using the format _s_t_a_r_t-_e_n_d or
          _s_t_a_r_t:_e_n_d or _s_t_a_r_t:+_n_a_n.  Either _s_t_a_r_t or  _e_n_d  may  be
          omitted,  in  which case the omitted parameter defaults
          respectively to the start or end of the input SD file.

     ----rrrr _r_a_n_g_e
          rrrr is a synonym for pppp.

     ----mmmm _a_n_a_l__m_e_t_h_o_d[mburg]



        Copyright Entropic Research Laboratory, Inc. 1G1        1






LPCANA(1-ESPS)                              ENTROPIC RESEARCH LAB



          Specifies the spectrum analysis method.  The default is
          the modified Burg method.  Also available are the auto-
          correlation method ("autoc"), ovariance method ("cov"),
          Burg   method   ("burg"),  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.  The ----mmmm
          option overrides the value that may be in the parameter
          file.  The default applies only if there is no value in
          the parameter file.

     ----FFFF    Specifies use of the framing method  of  the  previous
          version of _r_e_f_c_o_f, in which the reflection coefficients
          for each pulse in an analysis frame are determined by a
          spectral  analysis  of  the entire frame.  If ----FFFF is not
          used, an additional spectrum analysis is performed  for
          each pulse.

     ----xxxx _d_e_b_u_g__l_e_v_e_l [0]
          option specifies that various information or  debugging
          messages be printed on standard error.

EEEESSSSPPPPSSSS HHHHEEEEAAAADDDDEEEERRRR
     The generic header item _s_t_a_r_t__t_i_m_e (type DOUBLE) is  written
     in the output file.  The value written is computed by taking
     the _s_t_a_r_t__t_i_m_e value from the header of the input  file  (or
     zero,  if such a header item doesn't exist) and adding to it
     the offset time (from the beginning of the  input  file)  of
     the first point or record processed.  Unlike many other ESPS
     programs, _l_p_c_a_n_a does _n_o_t  write  the  generic  header  item
     _r_e_c_o_r_d__f_r_e_q  (used by _w_a_v_e_s+ for time synchronization); this
     is because the output records  from  _l_p_c_a_n_a  result  from  a
     variable frame length analysis.

     The following generic header items are added (in addition to
     the standard ones (FEA_ANA-5):

          _p__o_f_f_s_e_t - _i_n_t_e_g_e_r

          How many points before the beginning of the  pulse  the
          spectrum analysis window is started.


          _d_c_r_e_m - _s_t_r_i_n_g

          Yes means that the DC component was removed before  the
          data was analyzed.





        Copyright Entropic Research Laboratory, Inc. 2G2        2






LPCANA(1-ESPS)                              ENTROPIC RESEARCH LAB



          _p_s_y_n_c_h - _s_t_r_i_n_g

          Yes means that the spectrum analysis is done pitch syn-
          chronously.


          _m_a_t_s_i_z - _i_n_t_e_g_e_r

          The size of the autocorrelation matrix that was used in
          the spectrum analysis.


EEEESSSSPPPPSSSS PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
     The values of parameters obtained from  the  parameter  file
     are printed if the environment variable ESPS_VERBOSE is 3 or
     greater.  The default value is 3.  The following  parameters
     are read from the parameter file:

          _s_t_a_r_t - _i_n_t_e_g_e_r

          This is the starting point  in  the  input  file.   Its
          value is superseded by a ----pppp value. The default value is
          1.


          _n_a_n - _i_n_t_e_g_e_r

          This is the number of points to analyze. Its  value  is
          superseded by a ----pppp value.


          _l_p_c__f_i_l_t_e_r__o_r_d_e_r - _i_n_t_e_g_e_r

          This is the order of the linear prediction filter  that
          represents the vocal tract.  The maximum allowable size
          is 20.  The default value is 10.

          _l_p_c__f_r_a_m_e__s_i_z_e - _i_n_t_e_g_e_r

          This is the nominal frame size for performing  spectral
          analysis. The default value is 160.

          _m_i_n_i_m_u_m__p_u_l_s_e__l_e_n_g_t_h - _i_n_t_e_g_e_r

          This specifies the minimum pitch period. The  algorithm
          has  been well tested for the pitch range of 50-400 Hz.
          Thus a typical value of this variable is 20, assuming a
          sampling rate of 8000 Hz.  The default value is 20.

          _m_e_t_h_o_d - _s_t_r_i_n_g

          The spectrum analysis method  to  use.   The  available



        Copyright Entropic Research Laboratory, Inc. 3G3        3






LPCANA(1-ESPS)                              ENTROPIC RESEARCH LAB



          methods   are   autocorrelation  ("autoc"),  covariance
          ("covar"), Burg ("burg"), modified Burg ("mburg"), fast
          modified  Burg  method  ("fburg"), stuctured covariance
          ("strcov" and "strcov1"), and vector Burg  ("vburg",  a
          fast  approximation  to  structured  covariance.  If no
          value is given in the file, the modified Burg method is
          used  by  default.   The  _m_e_t_h_o_d  is  not read from the
          parameter file if the command line option ----mmmm is used.

EEEESSSSPPPPSSSS CCCCOOOOMMMMMMMMOOOONNNN
     If the input is standard input, COMMON is not read. If  COM-
     MON  is  read and the command line input filename does match
     the filename listed in COMMON then, the following items  are
     read.  If  the  two  filenames do not match, then no further
     parameters are read from COMMON.

          _s_t_a_r_t - _i_n_t_e_g_e_r

          This is the starting point in the input file.  Any  ---- pppp
          option value supersedes the COMMON specified value.

          _n_a_n - _i_n_t_e_g_e_r

          This is the number of points to analyze. A ----pppp specified
          value supersedes the COMMON specified value.

     ESPS Common  processing  may  be  disabled  by  setting  the
     environment  variable USE_ESPS_COMMON to "off".  The default
     ESPS Common file is .espscom in the user's  home  directory.
     This  may  be  overidden by setting the environment variable
     ESPSCOM to the desired path.  User feedback of  Common  pro-
     cessing   is   determined   by   the   environment  variable
     ESPS_VERBOSE, with 0 causing no feedback and increasing lev-
     els causing increasingly detailed feedback.  If ESPS_VERBOSE
     is not defined, a default value of 3 is assumed.

CCCCOOOOMMMMMMMMEEEENNNNTTTTSSSS
     The algorithm has been developed for speech sampled at  8000
     Hz.  It  works  best  when the data is recorded using a good
     microphone. Its quality is degraded, when working with tele-
     phone speech (especially if carbon microphone is used).

     The speech data is not pre-emphasized prior to LPC analysis,
     and  the  modified Burg method is used for computing the LPC
     parameters.

FFFFUUUUTTTTUUUURRRREEEE CCCCHHHHAAAANNNNGGGGEEEESSSS
     NONE.

BBBBUUUUGGGGSSSS
     If the input data consists of a long string  of  zeros,  the
     program bombs.



        Copyright Entropic Research Laboratory, Inc. 4G4        4






LPCANA(1-ESPS)                              ENTROPIC RESEARCH LAB



SSSSEEEEEEEE AAAALLLLSSSSOOOO
     _r_e_f_c_o_f (1-ESPS), _l_p_c_s_y_n_t (1-ESPS), FEA_ANA (5-ESPS),
     _F_E_A__S_D (5-ESPS), _c_o_m_p_u_t_e__r_c (3-ESPSsp)

AAAAUUUUTTTTHHHHOOOORRRR
     S. Shankar Narayan.  ESPS 3.0 modification by David  Burton.
     Modified for _c_o_m_p_u_t_e__r_c (3-ESPSsp) and for single-pulse out-
     put by John Shore.















































        Copyright Entropic Research Laboratory, Inc. 5G5        5