Filter Design Toolbox™

cost - Cost of using discrete-time or multirate filter

Syntax

c = cost(hd) c = cost(hm)

Description

c = cost(hd) and c = cost(hm) return a cost estimate c for the filter hd or hm. The returned cost estimate contains the following fields.

Estimated Value	Property	Description
`Number of Multiplications`	`nmult`	Number of multiplications during the filter run. `nmult` ignores multiplications by -1, 0, and 1 in the total multiple.
`Number of Additions`	`nadd`	Number of additions during the filter run.
`Number of States`	`nstates`	Number of states the filter uses.
`MultPerInputSample`	`multperinputsample`	Number of multiplication operations performed for each input sample
`AddPerInputSample`	`addperinputsample`	Number of addition operations performed for each input sample

Examples

These examples show you the cost method applied to dfilt and mfilt objects.

hd = design(fdesign.lowpass);
c = cost(hd)
c =
 
Number of Multipliers : 43
Number of Adders      : 42
Number of States      : 42
MultPerInputSample    : 43
AddPerInputSample     : 42
hd
 
hd =
 
     FilterStructure: 'Direct-Form FIR'
          Arithmetic: 'double'         
           Numerator: [1x43 double]    
    PersistentMemory: false

When you are using a multirate filter object, cost works the same way.

d = fdesign.decimator(4,'cic');
hm = design(d,'multisection')
 
hm =
 
  FilterStructure: 'Cascaded Integrator-Comb Decimator'
       Arithmetic: 'fixed'
DifferentialDelay: 1
 NumberOfSections: 2
 DecimationFactor: 4
 PersistentMemory: false
 
 InputWordLength: 16             
 InputFracLength: 15             
 
 FilterInternals: 'FullPrecision'

c=cost(hm)
 
c =
 
Number of Multipliers : 0  
Number of Adders      : 4  
Number of States      : 4  
MultPerInputSample    : 0  
AddPerInputSample     : 2.5

cost - Cost of using discrete-time or multirate filter

Syntax

Description

Examples

See Also