A human male produces sperms with the genotypes AB, Ab, aB and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

A person with the genotype $AaBb$ is a double heterozygote. During meiosis, due to independent assortment, this individual will produce four types of gametes (AB, Ab, aB, ab) in equal proportions ($25\%$ each).