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ST-Computer Leser 1998 October
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STC_CD_10_1998.iso
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UTILITY
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FILTERS
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README.TXT
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1998-09-26
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**********************************************************************
FILTERS 1.997
by Julien Dehaese
**********************************************************************
Parce que ce monde est plurilinguiste, la brève notice d'explications est
écrite en anglais. En aucun cas l'auteur ne pourra être tenu pour
responsable des conséquences dûes à l'installation et/ou l'utilisation de
ce programme ou d'autres programmes. Ce programme est freeware.
Because this world is multilingual, the user's manual is written in
English. The author cannot be considered as responsible for any
consequence due to the installation and/or the use of this program or
other programs. This program is freeware.
ACKNOWLEDGEMENTS
My thanks to Mathias Agopian whose filter routines and explanations he
included in STMAG helped me develop this accessory.
My thanks to my brother Simon for his very useful pieces of advice
without which I would probably be still programming.
I- INTRODUCTION
FILTERS 1.997 is an accessory that uses the Falcon030 DSP to filter
sound data in real time. This accessory can be used alone or with a
suitable audio program to play or record data while filtering
(Audiocreate 2.81 or the coming soon 3.0 for instance).
About the filter algorithm:
Type:
Finite Impulse Response (FIR)
Order:
127
Windowing available:
Rectangular (13 dB attenuation between the first and the second lobe)
Hanning (32 dB attenuation between the first and the second lobe)
Hamming (43 dB attenuation between the first and the second lobe)
Blackman (58 dB attenuation between the first and the second lobe)
Available filters:
Passe-bas (Lowpass)
Passe-haut (Highpass)
Passe-bande (Bandpass)
Coupe-bande (Bandcut)
II- INSTALLATION
Unpack the file FILTERS.ZIP
Place the file FILTERS.ACC in the boot drive
Reboot
III- UTILISATION
3.1- Connect your devices
Prepare your prefered CD and arrange your devices so that it be linked to
the Falcon's (audio) input. Arrange them also so as to hear the Falcon's
(audio) output.
3.1a- Without any other program
Go to the menu "DESK". Click on "FILTERS 1.997". The user interface
appears. Follow the steps indicated below:
1- Set the sampling frequency in Hz (box fréq. d'échant.)
Note: Setting the sampling frequency may change the other settings.
Indeed, the program takes into account Shannon's theorem: if the
sampling frequency is X Hz, the highest frequency you can hear is
X/2 Hz.
Thus, there is no possibility to filter with inconsistent parameters.
2- Select the type of the filter and a window (Rect., Hanning...)
3- If lowpass or lowcut is selected, you can change the cutting
frequency by setting it in the top right box (Passe bas/haut)
If the other filters are selected, you can change the lower
(resp. upper) frequency by setting it in the bottom left (resp.
bottom right) box.
Changing the parameters affects the DSP algorithm in real
time.
3.2- With another program
Start the other program and follow the procedure explained in ▌3.1a.
3.3- With Audiocreate release 2.8 and later
Start Audiocreate.
To record using FILTERS, go in "Preferences", "Enregistrement", and set
the flag "Traitement DSP". Then, follow ▌3.1a. Audiocreate connects
appropriatly the matrix so that the DSP modify the input signal.
To play using FILTERS, go in "Preferences", "Ecoute", and set the flag
"Traitement DSP". Then, follow ▌3.1a. Audiocreate connects
appropriatly the matrix so that the DSP modify the output signal.
3.4- To quit, click on the upper left corner of the window. The program
demands whether you want to leave with the sound active or inactive.
Click on "Son actif" to let it active. Click on the other box to
desactivate it.
IV- CONTACT
For feedback concerning this accessory, contact me at the following
address:
Julien Dehaese
23, rue Paul Boulanger
60120 CAPLY, FRANCE
dehaese@dyadel.net
For feedback, information, or registration concerning Audiocreate,
contact Simon Dehaese at the same address, same email.
Filter in peace.
Julien Dehaese.