ECG Database Applications Guide Table of Contents

NAME

a2m, ad2m, m2a, md2a - utilities for converting between MIT and AHA DB formats

SYNOPSIS

a2m -i ahafile -r record -a annotator [ options ... ]
ad2m -i ahafile -r record [ options ... ]
m2a -r record -a MIT-annotator AHA-annotator [ options ... ]
md2a -o ahafile -r record [ options ... ]

DESCRIPTION

These programs can be used to convert AHA DB distribution files from half-inch 9-track tape or floppy disks to MIT format (i.e., formats that can be read directly by programs compiled with the db(3) library), or to convert files in MIT format into AHA DB tape distribution format (conversion to AHA DB floppy disk distribution format is not supported). All four of these programs print a brief usage summary if invoked with no command-line arguments, or with a -h option.

Use a2m to convert AHA-format annotation files into MIT format. Options for a2m include:

-s time
Shift annotations forward by the specified time (default: no shift for type 0 input files, 5 minutes for type 1 or 3, or 2 hours and 30 minutes for type 2).
-t type
Convert an input file of the specified type (0: a file produced by a DB application using putann and `AHA_WRITE' mode; 1: an AHA DB `short format' tape file; 2: an AHA DB `long format' tape file; 3: an AHA DB compressed (*.ano) floppy disk file). Input files of types 1, 2, and 3 are assumed to contain annotation times in milliseconds, which are converted to sampling intervals based on an assumed sampling frequency of 250 Hz.

Use ad2m to convert AHA-format signal files into MIT format. Options for ad2m include:

-c
Convert an AHA DB compressed (*.cmp) floppy disk file (default: convert a file in AHA DB tape format).
-f time
Begin converting at the specified time relative to the beginning of the input file (default: 0, i.e., at the beginning of the input file)
-t time
Stop converting at the specified time relative to the beginning of the input file (default: 35 minutes after the starting time, or the end of the input file, whichever comes first).

Use m2a to convert MIT-format annotation files into AHA tape format. Options for m2a include:

-s time
Shift annotation times backward by the specified time, and convert them from sample intervals to milliseconds.

Use md2a to convert MIT-format signal files into AHA tape format. Options for md2a include:

-n new-record
Create a new header file for the AHA-format output signal file, so that it may be read as record new-record.

MIT-format files can be excerpted and reformatted in more generally useful ways using snip(1) or xform(1) .

The shell variable DB should be set and exported (see setdb(1) ).

EXAMPLES

AHA DB floppy disk

To make a version of AHA DB record 1201 in MIT format, given the distribution floppy disk, copy the files 1201.ano and 1201.cmp to the current directory, then type:
   ad2m -i 1201.cmp -r 1201 -c
   a2m -i 1201.ano -r 1201 -a atruth -t 3
These commands produce files 1201.dat (the signal file), header.1201 (the header file, named 1201.hea under MS-DOS), and atruth.1201 (the reference annotation file, named 1201.atr under MS-DOS), all in the current directory. Run ad2m first, so that the new header file is available for the use of a2m.

AHA DB short format tape

To obtain the same files given a `short format' 9-track distribution tape, copy the second and third files from the tape into files 1201.tap and 1201.ann in the current directory, then type:
   ad2m -i 1201.tap -r 1201
   a2m -i 1201.ann -r 1201 -a atruth -t 1
The names for the files copied from the tape are arbitrary, but do not use names of files to be generated by ad2m or a2m (see the previous example). Note that the first and fourth files on the distribution tape contain an `id' block, which can be read by readid (a program included in the convert directory of the DB Software Package) to verify the record name. Distribution tapes that contain more than one record contain additional sets of four files, always in the same order within each set.

AHA DB long format tape

To make a version of the three-hour AHA DB record 1001 in MIT format, given the `long format' distribution tape, copy the second and third files from the tape into files 1001.tap and 1001.ann in the current directory, then type:
   ad2m -i 1001.tap -r 1001 -t 3:0:0
   a2m -i 1001.ann -r 1001 -a atruth -t 2
The -t 3:0:0 option is necessary to prevent ad2m from truncating the signal file after the first 35 minutes.

Converting AHA DB long format to short format

To make a version of AHA DB record 1201 in MIT format, given a `long format' 9-track distribution tape containing the corresponding three-hour record 1001, copy the second and third files from the tape into files 1001.tap and 1001.ann in the current directory, then type:
   ad2m -i 1001.tap -r 1201 -f 2:25:0
   a2m -i 1001.ann -r 1201 -a atruth -t 1
In this case, the -f option instructs ad2m to skip the first two hours and 25 minutes of the `long-format' AHA signal file, and to reformat the remainder (equivalent to the 35-minute `short-format' record). The -t 1 option is used with a2m even though its input file comes from a `long-format' tape, because the annotation times must be shifted only by the amount necessary for a `short-format' tape in this case.

Sharing signal files for long format and short format AHA DB records

To keep both versions (1001 and 1201) on-line, make the `long format' version first (see above), then type:
   a2m -i 1001.ann -r 1201 -a atruth -t 1
to make a `short format' reference annotation file. Continue (under UNIX) by:
   cp header.1001 header.1201
or (under MS-DOS) by:
   copy 1001.hea 1201.hea
and edit the copy of the header file, replacing `1001' in the first line (only!) with `1201', and replacing `212' in the second and third lines by `212+6525000' (see the description of the `byte offset' field in header(5) ). Although two header and reference annotation files are needed, both versions can share the same signal file, allowing a substantial savings in storage requirements. Note that DB application programs that read the `short format' record 1201 signal file may report signal checksum errors at the end of the record, unless you also recalculate the signal checksums (easily done using snip(1) to copy the record; delete the copy once the checksums have been obtained).

AVAILABILITY

These programs are provided in the convert directory of the DB Software Package. Run make in that directory to compile and install them if they have not been installed already.

SEE ALSO

snip(1) , xform(1) , db(3) , header(5)


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