Universal sampling rate converter in electronic devices and methods
View Patent ↗A method and apparatus for converting the sampling rate of digital signals including a decimating comprising a low pass filter ( 122 ) and a downsampler ( 124 ), wherein the input signal is decimated a number of times based on a ratio of an input sampling rate to an output sampling rate. The exemplary apparatus also includes an upsampler ( 130 ) and another decimator ( 140 ) wherein the signal is upsampled after decimating if a ratio of the input sampling rate to an output sampling rate is not a power of an integer number.
1. A method in a digital signal sampling rate converter that reduces a sampling rate of an input signal, the method comprising:
decimating the input signal a number of times based on a ratio of the input sampling rate to an output sampling rate;
upsampling and decimating again and after repeatedly decimating if a condition is satisfied.
2. The method of claim 1 , upsampling and decimating again after decimating a number of times if a ratio of the input sampling rate to the output sampling rate is not equal to a power of some integer value.
3. The method of claim 1 , reducing a bandwidth of the input signal when decimating.
4. The method of claim 3 , reducing the bandwidth of the input signal so that the output sampling rate is greater than a multiple of 2 times the reduced bandwidth of the input signal.
5. The method of claim 1 , each decimation of the input signal includes a lowpass filtering step and a downsampling step.
6. The method of claim 1 , decimating the input signal a number of times based on a logarithm of the ratio of the input sampling rate to the output sampling rate.
7. The method of claim 1 , decimating the input signal a number of times using a single decimator.
8. A method in a digital signal sampling rate converter, the method comprising:
decimating an input signal an input sampling,
decimating includes low pass filtering and downsampling;
upsampling and decimating again after decimating the input signal only if a ratio of the input sampling rate to an output sampling rate is not a power of an integer number,
the output sampling rate less than the input sampling rate.
9. The method of claim 8 , decimating the input signal repeatedly by decimating the input signal a number of times based on a logarithm of the ratio of the input sampling rate to the output sampling rate.
10. The method of claim 8 , reducing the bandwidth of the input signal sampled at the first rate such that the output sampling rate is greater than a multiple of 2 times the reduced bandwidth of the input signal.
11. A method in a universal digital signal sampling rate converter, the method comprising:
downsampling an input signal;
upsampling and decimating again after downsampling the input signal only if a ratio of an input sampling rate to an output sampling rate is not equal to a power of an integer number.
12. The method of claim 11 , downsampling by decimating the input signal a number of times based on a ratio of the input sampling rate to the output sampling rate.
13. The method of claim 12 , decimating includes an act of low pass filtering followed by an act of downsampling.