Are all FIR filters causal?

Are all FIR filters causal?

Recall from §5.3 that any LTI filter having a zero impulse response prior to time 0 is said to be causal. Thus, a tapped delay line such as that depicted in Fig. 5.5 can only implement causal FIR filters.

Can IIR filters be causal?

(v) An IIR filter is linear and time-invariant. (vi) It is causal. (We only consider causal IIR filters.) (vii) Its order is usually defined to be N, though this is not a universal convention.

What is the advantage of MATLAB’s filtfilt?

MATLAB’s filtfilt does a forward-backward filtering, i.e., filter, reverse the signal, filter again and then reverse again. Apparently this done to reduce phase lags? What are the advantages/disadvantages of using such a filtering (I guess it would result in an effective increase in filter order).

How are IIR filters used in MATLAB software?

Although IIR filters have nonlinear phase, data processing within MATLAB ® software is commonly performed “offline,” that is, the entire data sequence is available prior to filtering. This allows for a noncausal, zero-phase filtering approach (via the filtfilt function), which eliminates the nonlinear phase distortion of an IIR filter.

Is there an anti-causal zero phase filter?

Anti-Causal, Zero-Phase Filter Implementation. In the case of FIR filters, it is possible to design linear phase filters that, when applied to data (using filter or conv ), simply delay the output by a fixed number of samples. For IIR filters, however, the phase distortion is usually highly nonlinear.

What is the advantage of a non-causal filter?

When you implement a non-causal filter, transients get blurred forwards and backwards (e.g. if we want a 2dB ripple, the fact that we’re going to be making a forward and backward run using the filter means that we’ll want each of these to have 1dB). Uses the time-reversal property of the discrete-time Fourier transform.