Modelling Unknown System 2 - Essay Example

There are various design methods of IIR filter used, with the analogue reference prototype filter being the most commonly used method, as it is suitable for the design of low pass filters, high pass, band stop filters and band pass filters. Reference type, analog prototype filter, to be used is specified according to its requirements and specification then there is design of the analog prototype filter. Scaling of the analog prototype filter into the required frequency range succeeds the design phase.

The scaling process converts the analogue prototype into an analog filter. The last step is the conversion from analog to digital filter. Bilinear transformation method converts analogue filters to digital filters. The resulting filter, obtained is always stable, but, instability of the resulting filter may only be caused by the finite word-length side-effect [1]. The design process of the desirable IIR filter commences with the specification and requirements. The reference prototype analogue filter is chosen based on the specification.

Scaling of the analogue prototype filter frequency into the desired range succeeds the design phase. The prototype filter is, thus, converted into an analogue filter. The final step is the conversion to digital filter from the analogue filter type by the use of the bilinear transformation method for conversion. The conversion process achieves a stable filter though instability may result from finite word length side effects [1]. Finite impulse response filter equalizes the natural channel response into a partial response target to reduce the complexity of the corresponding maximum sequence detector in magnetic recording.

The natural channel response may vary due to changes such as variation in the head medium separation, therefore, requiring the adaptation of finite impulse response. LMS algorithm based adaptation can also be used. It should be known that conflicting interactions among the LMS loop, the AGC (automatic gain control)