Why FIR uses often direct-form instead of transposed-form?

1. What is a direct form FIR filter?
2. What is the difference between the direct form structures and the transposed structures for different types of filters?
3. Why is FIR more stable?
4. Why FIR is preferred over IIR?

What is a direct form FIR filter?

FIR Direct Form. This is called “direct form” because it is a direct implementation of the convolution operation. The number of delays is equal to the order of the filter, hence this structure is canonic. It should be clear that. y[n] = h[0]x[n] + h[1]x[n - 1] + ··· + h[N]x[n - N] =

What is the difference between the direct form structures and the transposed structures for different types of filters?

Unlike the pipelined direct form structure, the transposed structure has limitations regarding the fanout of the input. This is due to the fact that the input is broadcast to all of the multipliers. Hence, the fanout of the input must be taken into account when we are designing a filter with a large number of taps.

Why is FIR more stable?

An FIR filter is a filter with no feedback in its equation. This can be an advantage because it makes an FIR filter inherently stable. Another advantage of FIR filters is the fact that they can produce linear phases. So, if an application requires linear phases, the decision is simple, an FIR filter must be used.

Why FIR is preferred over IIR?

IIR filters are well suited for applications that require no phase information, for example, for monitoring the signal amplitudes. FIR filters are better suited for applications that require a linear phase response.