Are Portuguese Jews Sephardic or Ashkenazi?

Could you please clarify for me the distinction between Sephardic and Ashkenazi Jews, and how it relates to the question of whether Portuguese Jews belong to one of these groups? I understand that there are historical and cultural differences between the two, but I'm not entirely sure how they apply to the specific case of Portuguese Jews. Could you elaborate on the origins and characteristics of each group, and explain which one Portuguese Jews are typically classified as?