Abstract: A sampling apparatus for converting first data, sampled at a first sampling rate, into second data, sampled at a second sampling rate. A FIFO storing the first data based on a write control signal and outputs the second data read out based on a read control signal indicating whether the second data is to be read out during the next time interval. The apparatus further includes a frequency detection unit for measuring the first clock signal during the current time interval to generate the value of the first current clock frequency, generating the value of a current predicted clock frequency from the value of the first current clock frequency and the value of the directly previously predicted clock frequency and for using the value of the current predicted clock frequency as the directly previously predicted clock frequency during the next time interval.

Abstract: Disclosed is a sampling rate conversion apparatus for converting first data, sampled at a first sampling rate, into second data, sampled at a second sampling rate, includes a FIFO for storing the first data responsive to a first clock signal and for outputting the first data as second data responsive to the second clock signal. This FIFO stores the first data based on a write control signal indicating whether or not the first data written directly previously is to be updated to the first data, and outputs the second data read out based on a read control signal indicating whether or not the second data as read out is to be read out during the next time interval as well.

Abstract: There is disclosed an ATM layer device configured to realize the function of an ATM layer by selecting one from a plurality of physical layer devices realizing the function of a physical layer, and executing a transfer of a cell, which is a unit of transmission, between the ATM layer device and the selected physical layer device. Priority information indicating the previously set priority level of each of said plurality of physical layer devices is held, and the physical layer device which should execute the cell transfer is selected in a predetermined order in accordance with the priority information. Thus, drops in cell transmission rate and receiving buffer overflows in the physical layer device are eliminated.