Combination of two signals with different sample rates

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Hello,
I want to combine two signals with different sampling rate. I have have 2 sound signals, one (A) has telephone quality (Fs = 8Kz) and the other (B) music CD quality(Fs = 44.1 KHz). I want to add the music from file B to file A as a music investment (need someweakening). The duration of the result is equal to the longer of A and B.
How i can manage it??
  5 Comments
Mathieu NOE
Mathieu NOE on 13 Jun 2022
Edited: Mathieu NOE on 13 Jun 2022
hmmm
that depends if the signal sampled at 44.1 kHz should not be downsampled because it contains valuable info in the high frequency range ( 4 to 22 kHz)
beside that , upsampling does not create "noticable" / bad info's if it's done correctly :
  • for real time upsampling : insert zero elements AND then low pass filter (see for example : slidesSampling.dvi (toronto.edu)
  • for non real time upsampling : you can do the same , or simply interpolation. A higher order interpolation will almost create zero artifacts / info in the "new" frequency range. You can try it , do the upsampling and make the fft of the upsampled signal vs the original signal. You will end up will a almost zero fft amplitude in the extended frequency range. BTW, interp1 does not require any toolbox.

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Answers (1)

Peter Perkins
Peter Perkins on 13 Jun 2022
Use a timetable, and call synchronize. synchronize uses interp1, but it may be that you particularly want to use the SP-oriented resample function instead:
ttHighFreq.yUpsampled = resample(ttLowFreq.y,...)

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