Patent ID: 7570727
Filing Date: 2009-08-04
Classification: G06F,H04H,H04J,H04L

Abstract:
1. A sampling frequency converter apparatus comprising: an interpolation part that interpolates data according to an interpolation ratio; and a transmission control part that transmits the interpolated data based on frequency control information, wherein the interpolation part comprises: a holding portion that successively receives data having a first sampling frequency and holds the received data as an interpolation input string of the data; and an interpolating portion that generates the interpolated data having a second sampling frequency by performing interpolation using an interpolation coefficient corresponding to the interpolation ratio generated by the transmission control part and using the interpolation input string of the data held in the holding portion, and wherein the transmission control part comprises: a first-in first-out storage portion that is responsive to a write request signal for storing the interpolated data being outputted from the interpolation part and having the second sampling frequency, and that reads and outputs the stored data which has been stored earliest in response to a read request signal; a remaining data amount detection portion that detects a remaining data amount of the data stored in the first-in first-out storage portion; a variable frequency oscillating portion that generates an enable signal at a time rate according to the frequency control information so as to enable generation of the write request signal, and that generates the interpolation ratio varying at a speed according to the frequency control information; and a frequency control portion that corrects the frequency control information so as to return the remaining data amount to an appropriate value when the remaining data amount detected by the remaining data amount detection portion varies away from the appropriate value toward an upper limit value or varies away from the appropriate value toward a lower limit value, or when the remaining data amount reaches the upper limit value or the lower limit value.