SDXC cards are SD cards but with a much higher capacity and faster processing speeds. They have a maximum capacity of 2TB (Terabytes).
This video camera's memory card type (SDXC) is in fact the best supported memory card type across all comparable spec video cameras that have been on the market for around the same time as the FDR-AX33.
A MicroSDXC memory card is the worst supported memory card type amongst similar types of video camera.
SDHC cards are DS cards with a higher capacity of up to 32GB.