Apparatus for giving marks on user's singing ability in karaoke

Claim 1

An apperatus for giving marks on a user's singing ability in a karaoke system comprising: a first A/D converter for converting first analog signals produced in a karaoke accompaniment signal source into first digital signals; a first digital filter for filtering first passband signals among said first digital signals; an amplifier for amplifying second analog signals produced in a microphone voice signals source; a second A/D converter for converting the amplified second analog signals into second digital signals; a second digital filter for filtering second passband signals among said second digital signals; a cross-correlator for operating the first passband signals and said second passband signals in cross-correlation mode to produce a correlated signal; a first mean producing part for producing first mean signals from said first correlated signal; a first auto-correlator for operating said first passband signals in an auto-correlation mode to produce first auto-correlated signals; a second auto-correlator for operating said second passband signals in an auto-correlation mode to produce second auto-correlated signals; a second mean producing part for producing second mean signals from said second auto-correlated signals; a third mean producing part for producing third mean signals from said cross-correlated signals; and a normalizer for normalizing said first mean signals and, said second mean signals and third mean signals to produce a signal for giving marks.