


DOWN210(SFS1)     MISC. REFERENCE MANUAL PAGES      DOWN210(SFS1)



NAME
     down210 - filter and downsample 12.8kHz & 20kHz waveforms to
     10kHz

SYNOPSIS
     down210 (-i item) (-2) file

DESCRIPTION
     down210 is a program to filter and downsample a  12.8kHz  or
     20kHz  waveform to 10kHz.  For 20KHz waveforms, the waveform
     is filtered forwards and  backwards  with  an  IIR  low-pass
     filter  with  a  3db point at 5kHz.  It is best to acquire a
     20kHz signal with the anti-aliasing  filter  set  to  either
     6.4kHz or 8kHz so as not to disturb the spectrum below 5kHz.
     For 12.8kHz waveforms, the IEEE sampling rate converter rou-
     tine  is  used.   This upsamples to 320kHz and applies a FIR
     low-pass filter at 5kHz before downsampling.

     Options and their meanings are:

     -I         Identify program and version number.

     -iitem     Select input item number.

     -2         Filter and downsample lx waveform.

INPUT ITEMS
     1.xx       Any 12.8kHz or 20kHz speech waveform.

     2.xx       (Or) Any 12.8kHz or 20kHz excitation waveform.

OUTPUT ITEMS
     1          Filtered and down-sampled waveform.

     2          (Optional) Filtered and down-sampled waveform.

FILES
     /usr/dbase/data/down210.filt
                FIR filter for 12.8kHz waveforms: 1023  tap  low-
                pass at 5kHz for 320kHz sampling.

VERSION/AUTHOR
     1.2 - Mark Huckvale.

SEE ALSO
     agc, differ

SOURCE
     /users/mark/sfs/man/../ucl/HQ.src/down210.c






Sun Release 4.1         Last change: UCL                        1



