Fixed-point Implementation of FIR coefficients

Hi,

I am using Matlab R2010a (R2009b) and I installed the fixed-point toolbox. To redesign a filter I am taking the following steps:

1. specify the filters parameters in FDA tool 2. export the coefficients (double values) to workspace 3. Run coesave.m and coewrite.m codes to change these values from double to fixed-point suitable for Xilinx implementation.

However, I encounter several errors:

1. set(hq,'arithmetic','fixed'); I also tried hq.Arithmetic='fixed'; but the same error occurs: ??? Changing the 'Arithmetic' property of dfilt.dffir is not allowed.

2. I used hq.Numerator = fi(hq.Numerator); instead but then inside coewrite.m: if ~isfixed(Hq.coefficientformat), ??? No appropriate method, property, or field coefficientformat for class dfilt.dffir.

3. I commented out the line related to error #2. Then on line: strheader = sptfileheader('XILINX CORE Generator(tm) Distributed Arithmetic FIR filter coefficient (.COE) File', ... 'filterdesign', ';'); the following error occurred: ??? Index exceeds matrix dimensions.

4. I commented out error #3 as well. On line: fprintf(fid,'Coefficient_Width = %d; \n',Hq.coefficientformat.wordlength);

 ??? No appropriate method, property, or field coefficientformat for class dfilt.dffir.

5. After commented out the error #4. Another error on line: q = get(Hq,'CoefficientFormat');

??? There is no 'CoefficientFormat' property in the 'dffir' class.

I would appreciate it if you could help me find a solution for this problem.

Thanks,

Nazila