tuhaf bir sesin beni uyandirmasina ne kadar şaşirdigimi tahmin edebilirsiniz
The only think I do not understand here is why uyandirmak has "-masina" as a suffix
My knowledge about such construction does not give sense to the sentence
uyandirma (short infinitive) +si (someone's) +na (dative) ( I guess since "ne kadar)
but, that will mean "someone's sleeping", while in the sentence it is the sleeping of the one who is telling the story, the "beni".
What am I missing?