kobeml
Newbie level 1
hi,
Can someone explain how I can compensate for sampling clock frequency offset (SCO) using fractional-delay interpolation? In OFDM basebnad receiver design book they said that you can use fractional-delay interpolation filter to compensate SCO but of course they forgot to write about.
Let's say I have a ramp signal (it will be easier for me to explain what my doubts are as it has amplitude equal to the time progress).
The ideal sampling case (sampling period at receiver = Tideal where Tideal=Ttransmitter):
T= [1 2 3 4 5 6 7 8]
Sample_value= [1 2 3 4 5 6 7 8]
Now I have an offset Toff (let's say 0.2*Tideal) so I sample with the period T=Tideal+Toff=1.2Tideal
T= [1 2 3 4 5 6 7 8 ...]
sample_value =[1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 ...]
When I use farrow fractional-delay filter it will interpolate at fixed offset but for correction purposes the offset changes from sample to sample because sampling periods are not equal (the fist sample is correct but the rest are not because for the 2nd sample the offset should 0.4 not 0.2 and so on).
Let's say I use 0.2 fractional delay:
T= [1 2 3 4 5 6 7 8 ...]
samples_values=[1 2.2 3.4 4.6 5.8 7 8.2 9.4]
How can I resample the received sampled data (sampled with period T=Tideal+0.2Tideal) [1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 ...] with the sample period Tideal so I get the desired data [1 2 3 4 5 6 7 8] using interpolation?
Can someone explain how I can compensate for sampling clock frequency offset (SCO) using fractional-delay interpolation? In OFDM basebnad receiver design book they said that you can use fractional-delay interpolation filter to compensate SCO but of course they forgot to write about.
Let's say I have a ramp signal (it will be easier for me to explain what my doubts are as it has amplitude equal to the time progress).
The ideal sampling case (sampling period at receiver = Tideal where Tideal=Ttransmitter):
T= [1 2 3 4 5 6 7 8]
Sample_value= [1 2 3 4 5 6 7 8]
Now I have an offset Toff (let's say 0.2*Tideal) so I sample with the period T=Tideal+Toff=1.2Tideal
T= [1 2 3 4 5 6 7 8 ...]
sample_value =[1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 ...]
When I use farrow fractional-delay filter it will interpolate at fixed offset but for correction purposes the offset changes from sample to sample because sampling periods are not equal (the fist sample is correct but the rest are not because for the 2nd sample the offset should 0.4 not 0.2 and so on).
Let's say I use 0.2 fractional delay:
T= [1 2 3 4 5 6 7 8 ...]
samples_values=[1 2.2 3.4 4.6 5.8 7 8.2 9.4]
How can I resample the received sampled data (sampled with period T=Tideal+0.2Tideal) [1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 ...] with the sample period Tideal so I get the desired data [1 2 3 4 5 6 7 8] using interpolation?