1. A method to match a hash value representing an unidentified information signal with a plurality of hash values stored in a database and to identify a respective one of a plurality of information signals, the method comprising: receiving said hash value in the form of a plurality of reliable hash bits and unreliable hash bits; searching in the database the stored hash values for which holds that the reliable bits of the applied hash value match the corresponding bits of the stored hash value while ignoring unreliable bits of the applied hash value and corresponding bits of the stored hash value; for each stored hash value found in response to the searching, calculating the bit error rate between the reliable bits of the hash value representing the unidentified information signal and the corresponding bits of the stored hash value; determining for which stored hash values the bit error rate is minimal; and returning an identification of the respective one of the plurality of information signals that corresponds to the minimal bit error rate.
1. A method to match a hash value representing an unidentified information signal with a plurality of hash values stored in a database and to identify a respective one of a plurality of information signals, the method comprising: receiving said hash value in the form of a plurality of reliable hash bits and unreliable hash bits; searching in the database the stored hash values for which holds that the reliable bits of the applied hash value match the corresponding bits of the stored hash value while ignoring unreliable bits of the applied hash value and corresponding bits of the stored hash value; for each stored hash value found in response to the searching, calculating the bit error rate between the reliable bits of the hash value representing the unidentified information signal and the corresponding bits of the stored hash value; determining for which stored hash values the bit error rate is minimal; and returning an identification of the respective one of the plurality of information signals that corresponds to the minimal bit error rate. 2. The method of claim 1 , further comprising generating the hash value, the generating of the hash value comprising: dividing the unidentified information signal into frames; computing a hash word for each frame; and concatenating successive hash words to constitute the hash value.