Contents
What is interpolation upsampling?
“Upsampling” is the process of inserting zero-valued samples between original samples to increase the sampling rate. (This is called “zero-stuffing”.) “Interpolation”, in the DSP sense, is the process of upsampling followed by filtering. (The filtering removes the undesired spectral images.)
Why is upsampling used?
The purpose of upsampling is to add samples to a signal, whilst maintaining its length with respect to time. Consider again a time signal of 10 seconds length with a sample rate of 1024Hz or samples per second that will have 10 x 1024 or 10240 samples.
Where is Upsampling used?
When upsampling is performed on a sequence of samples of a signal or other continuous function, it produces an approximation of the sequence that would have been obtained by sampling the signal at a higher rate (or density, as in the case of a photograph).
What is the effect of upsampling?
How does the interpolation filter affect the data rate?
When the additional samples are inserted zeros, they increase the data rate, but they have no effect on the frequency distribution until the zeros are replaced by the interpolation filter, depicted in the second graph. Its application makes the first two graphs resemble the third one.
When to use a multirate interpolating FIR filter?
The calculation performed by a multirate interpolating FIR filter for each output sample is a dot product: where the h [•] sequence is the impulse response, and K is the largest value of k for which h [ j + kL] is non-zero.
Which is a finite impulse response filter ( fir )?
A finite impulse response filter (FIR) of length N N which is placed before the upsampler needs to perform N N multiplications and N −1 N − 1 additions for each sample of x(n) x ( n).
What does expansion and interpolation mean in digital signal processing?
In digital signal processing, upsampling, expansion, and interpolation are terms associated with the process of resampling in a multi-rate digital signal processing system. Upsampling can be synonymous with expansion, or it can describe an entire process of expansion and filtering ( interpolation ).