(a) Field of the Invention
The present invention relates to a method and device for converting a data rate of a mobile communication transmitting/receiving system.
(b) Description of the Related Art
A presently existing mobile communication transmitting/receiving system may be used with synchronization or asynchronization of a clock of a baseband modem and a clock of a radio frequency (RF) transmitting/receiving terminal. A system in which a clock of a baseband modem and a clock of an RF transmitting/receiving terminal are operated with asynchronization requests a data rate conversion device that converts from a clock rate of the baseband modem to a clock rate of the RF transmitting/receiving terminal while minimizing noise.
A general rate conversion method includes a method of converting to a rational number rate, which is M/L. In order to convert to a rational number rate, which is M/L, a method of performing down-sampling of L times, passing through a low pass filter, and performing up-sampling of M times is used. In this case, when values of M and L are embodied with a large prime number, the low pass filter should be formed with hundreds of tabs and coefficients. Accordingly, another method is a method of using a Farrow filter. In a data rate conversion device of a Farrow filter structure, when embodying hardware, hardware complexity is low, but a metastability problem occurring when using an asynchronous clock and a phase offset problem occurring due to a phase error between asynchronous clocks exist, compared with the foregoing method. Further, a problem in that a clock frequency rate error that is generated in a measurement environment should be corrected exists.