ASCII download problem

Dear all,

I want to download a mysql database and store the content in ascii format.
Unfortunately, it is written in ANSI format.
How can I change the format from ANSI to ASCII during download ?

Just example, how it should work.

Thanks for any link or example.

Gerd

$query_text = "SELECT somedata from table";
$result = mysql_query($query_text, $connection);
Header("Content-Type: application/csv-tab-delimited-table");
Header("Content-disposition: filename=export.txt");
while ( $row = mysql_fetch_row($result)) {

php>??? convert $somedata to ascii ???<

print "$somedata"."\r\n";
}