Question

Design and implement a 3-band equaliser using a DSP board or MPLab/CSS. The  MATLAB Filter Designer could be used for filter design and graphing subject to  the design requirements given below. This is an individual CW 2. Equaliser Primer An n-band equaliser is a device used to correct the frequency response  characteristic of a signal processing system. Equalisers can be implemented using  digital or analogue filters. The whole bandwidth of the equaliser is divided into n  frequency bands, which can be individually amplified (a 3-band equaliser is  shown in Figure 1). Thus, any desired frequency characteristic can be  approximated. Very simple 3-band or 7-band equalisers are found in nearly every  modern hi-fi system. Basically, an n-band equaliser is implemented using a low  pass filter, a high pass filter and a set of n-2 band pass filters.   Design three filters  Low Pass  High pass  Band passSuggested requirements are as follows (Is this the best distribution for the  filters? Refer to deliverable (f). Equalizer bandwidth: 23 kHz Low pass band: 0  8 kHz Band pass band: 8  15 kHz  High pass band: 15  23 kHz  Pass band ripple: max. 6% Stop band rejection min 38 dB Mild phase distortions are acceptable. The pass band ripples apply also to the combination of the three filters. It is  expected that the frequency response of the 3 combined filters falls into a  band of 0.94 to 1.06 (assuming a normalised response). To achieve this, it  will be necessary to scale the individual filters. NB: The sampling frequency for this work is 48 KHz. 4. Design Hints  Either finite impulse response filters (FIR) or infinite impulse response filters  (IIR) can be used.  When using FIR filters, any type of window can be used. However, it might be  a good idea to think about a filter with a Hamming Window, a Hann Window  or a Kaiser Window.