What is difference between Direct form and Normal Direct form?

1. What is direct form?
2. What are the direct form structures?
3. What are the advantages of direct form 2 over direct form 1?
4. What is canonical form in DSP?

What is direct form?

In general, a direct form realization refers to a structure where the coefficients of the transfer function appear directly as Gain blocks. The direct form II realization method is presented as using the minimal number of delay elements, which is equal to n, the order of the transfer function denominator.

What are the direct form structures?

The IIR Direct Form structures usually require few mathematical operations. However, the sensitivity to finite word length effects limits the use of this form in fixed-point implementations. Use the IIR Cascaded Second-Order Sections Form structures to alleviate finite word length effects.

What are the advantages of direct form 2 over direct form 1?

The advantage of the direct form-II realization of continuous-time systems is that it uses minimum number of integrators. In this realization structure, an intermediate variable is integrated, instead of using the separate integrators for integrating the input and output variables separately.

What is canonical form in DSP?

Canonic filters are filters where the order of the transfer function matches the number of delay units in the filter. Conversely, Noncanonic filters are when the filter has more delay units than the order of the transfer function. In general, FIR filters are canonic.