Data receiving apparatus, a method of regenerating a source clock to be used for this, and a computer product

A data receiving apparatus comprising:

• a buffer unit which holds data that has been transmitted from a data transmitting apparatus to a transfer network at a constant speed based on a source clock, and that is then received from the transfer network at a constant speed;
• and
• a source clock regenerating unit detects a buffer remaining volume that is a data volume held by said buffer unit, and regenerates the source clock according to this buffer remaining volume, wherein
• said source clock regenerating unit having, an operating unit which obtains a weighted average value of a plurality of buffer remaining volumes that have been sequentially detected, multiplies a predetermined sensitivity coefficient to this weighted average value, and adds a predetermined offset value, thereby to obtain a control value for regenerating the source clock;
• and
• a control unit which sets a regeneration clock to a manipulated variable to be used for calculating the control value capable of converging to the source clock at a high speed during a period from when a source clock regeneration operation has started till when the regeneration clock satisfies a predetermined condition for coming closer to the source clock frequency, and for setting the regeneration clock to the manipulated variable capable of stably regenerating the source clock after this predetermined condition has been satisfied.