What does it mean to resample a sampling rate?
“Resampling” means combining interpolation and decimation to change the sampling rate by a rational factor. 4.1.2 Why resample? Resampling is usually done to interface two systems which have different sampling rates.
Do you always need a filter when resampling?
Yes. As always, the Nyquist criteria must be met relative to the resulting output sampling rate, or aliasing will result. In other words, the output rate cannot be less than twice the highest frequency (of interest) of the input signal. 4.1.5 When resampling, do I always need to a filter?
Is the resampling factor greater than one in multirate filtering?
Depending on the resampling factor, resampling can be thought of as a general case of other types of multirate filtering. It can be: Interpolation: The interpolation factor, L, is greater than one, and the decimation factor, M, is one.
How big is the interpolation factor for resampling?
No. The problem is that for resampling factors close to 1.0, the interpolation factor can be quite large. For example, in the case described above of changing from the sampling rate from 48 kHz to 44.1 kHz, the ratio is only 0.91875, yet the interpolation factor is 147!
Which is an example of the resampling factor?
The interpolation factor is simply the ratio of the output rate to the input rate. Given that the interpolation factor is L and the decimation factor is M, the resampling factor is L / M. In the above example, the resampling factor is 147 / 160 = 0.91875
How is a resampling filter used in a GSM system?
A resampling filter processes data from multiple standards using the same filter chain. The ratio of LTE and WCDMA baseband sample rates to that of GSM systems is 4608/325. This rate change factor makes the conventional polyphase implementation almost impossible.
What kind of upsampling does resample do?
Resample does upsampling / downsampling and the associated filtering, entirely in the frequency domain, using the Fourier Transform. Because it is using the Fourier Transform, a key assumption is that the signal that is fed in its input is periodic.
Which is an example of resampling in audio?
Resampling is usually done to interface two systems which have different sampling rates. A practical and well-known example results from the fact that professional audio equipment uses a sampling rate of 48 kHz, but consumer audio equipment uses a rate of 44.1 kHz.