What is decimation and interpolation of the signals?

Decimation and interpolation are the two basic building blocks in the multirate digital signal processing systems. The decimator is utilized to decrease the sampling rate and interpolator to increase the sampling rate.

What is interpolation and decimation in multirate signal processing?

The two basic operations in a multirate system are decreasing (decimation) and increasing (interpolation) the sampling-rate of a signal. Multirate systems are sometimes used for sampling-rate conversion, which involves both decimation and interpolation.

How is decimation done?

Loosely speaking, “decimation” is the process of reducing the sampling rate. In practice, this usually implies lowpass-filtering a signal, then throwing away some of its samples. “Downsampling” is a more specific term which refers to just the process of throwing away samples, without the lowpass filtering operation.

What is the effect of the decimation on frequency spectrum?

It states that after decimation, multiple frequency bands are mirrored into the same frequency region, as shown in Fig. 2(a). By re- moving the unwanted bands through an anti-alias filter, it is pos- sible to achieve an effect equivalent to the down conversion [see Fig. 2(b)].

How does a polyphase filter work?

A polyphase quadrature filter, or PQF, is a filter bank which splits an input signal into a given number N (mostly a power of 2) of equidistant sub-bands. These sub-bands are subsampled by a factor of N, so they are critically sampled.

What is decimation filtering?

Decimation is the process of reducing the sampling frequency of a signal to a lower sampling frequency that differs from the original frequency by an integer value. Decimation also is known as down-sampling. Decimation filters help you remove the excess bandwidth and reduce the sampling frequency of the signal.

What is interpolation in signal processing?

In the domain of digital signal processing, the term interpolation refers to the process of converting a sampled digital signal (such as a sampled audio signal) to that of a higher sampling rate (Upsampling) using various digital filtering techniques (for example, convolution with a frequency-limited impulse signal).

What is FIR decimation?

Description. The FIR Decimation block resamples vector or matrix inputs along the first dimension. The downsampler that follows downsamples each channel of filtered data by taking every M-th sample and discarding the M – 1 samples that follow. M is the value of the decimation factor that you specify.

Which LPF is used in the decimation process?

The HSP43220™ from HARRIS Corp. is a two-stage linear-phase FIR filter for decimation. The first stage, which is shown in Figure. 4.66, is a high-order decimation filter that allows decimation by factors up to 1024. The maximum input sample frequency is 30 MHz.

What is interpolation factor?

The interpolation factor is simply the ratio of the output rate to the input rate. It is usually symbolized by “L”, so output rate / input rate=L. Tip: You can remember that “L” is the symbol for interpolation factor by thinking of “interpo-L-ation”.

How does decimation affect bandwidth?

certainly downsampling (decimation) reduces the available bandwidth. if there is information at frequencies above the new Nyquist, that information is either lost or aliased (which also loses it).

What is polyphase implementation?

Polyphase is a way of doing sampling-rate conversion that leads to very efficient implementations. But more than that, it leads to very general viewpoints that are useful in building filter banks.