ESFILT

NAME

Esfilt - interactive waveform filtering

SYNOPSIS

Esfilt (-I) (-p) (-f filtfreq) (-h|-l|-w|-n) (-t print_title) (-i item) (-12) sfsfile

DESCRIPTION

Esfilt is a program to demonstrate filtering of speech and other waveforms. Four types of filter are built into the program, and can be specified by a single frequency parameter: high-pass, low-pass, wide-band-pass (300Hz), narrow-band-pass (45Hz). The program displays the original waveform at the top of the screen, the frequency response of the filter in the middle of the screen, and the output waveform at the bottom of the screen. A mouse click will select replay of either waveform. The selection of filter type and its frequency are made using keyboard commands. Options also allow printing the display and saving the filtered waveform back to the SFS file. The RMS amplitude of the input and output waveforms are displayed in Volts, assuming an ADC acquisition of 16-bits in the range -5 .. +5 V.

OPTIONS

-I Identify program name and version number.

-i item Specify input Speech or Lx Waveform item. Default: last speech item.

-p Direct output to printer. The program does not enter interactive mode. The screen image is recreated for the printer using filter specifications made using other command-line options.

-f filtfreq Set up initial filter frequency. Default 1000Hz.

-h Specify initial filter type as High-Pass.

-l Specify initial filter type as Low-Pass. Default.

-n Specify initial filter type as Narrow-Band-Pass.

-w Specify initial filter type as Wide-Band-Pass.

-t print_title Specify a title to appear on the printout. If no title is given then the date and time is printed instead.

-12 (null) Identify unmarked signals as 12-bits.

"MAIN MENU"

low-pass Select low-pass filter, requests edge frequency and re-draws display.

high-pass Select high-pass filter, requests edge frequency and re-draws display.

narrow-band Select narrow-band-pass filter, requests centre frequency and re-draws display.

wide-band Select wide-band-pass filter, requests centre frequency and re-draws display.

print Prints display. Requests a print title before printing in background.

save Saves currently filtered waveform to SFS file.

quit Exits program.

"MOUSE COMANDS"

middle Replays waveform under mouse pointer.

VERSION/AUTHOR

1.1 Mark Huckvale

Fri Jul 09 14:54:37 2004