To copy the files from a real tape, the first thing to do is to record the tape as a sound file (a good format to use is 48000Hz stereo 16 bit .WAV). This sound file should be processed (see below) and converted to headerless unsigned 8 bit format so that it can be read by the decode8 utility (this program is located in the tapeutil directory of the emulator sources). decode8 takes the name of the raw 8 bit sound file as command line argument, and extracts files in the current directory. Note that it prints a lot of messages to stderr, so it may be useful to redirect stderr to a file, and read this file (there may be error messages in case of problems with decoding files; this may easily happen with old tapes) after the decoding has been finished.
The tape decode utility expects a clean signal with maximum amplitude - this may not be the case with a sound file recorded from a tape. Thus, in most cases it is necessary to process the sound file before running decode8. If the tape is of good quality, it may be enough to apply a highpass filter with a low cutoff frequency to remove any DC offset and low frequency "bumps", and then amplify the signal by a factor of ten (20 dB) or more.
Back to ep128emu technical information
Back to ep128emu home page
© Istvan Varga
<istvan_v@mailbox.hu>, 2004, 2005