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info

Information about filter

Syntax

info(h)
info(h,'short')
info(h,'long')
s = info(h)

Description

info(h) returns very basic information about the filter. The particulars depend on the filter type and structure.

info(h,'short') returns the same information as info(h).

info(h,'long') returns the following information about the filter:

  • Specifications such as the filter structure and filter order

  • Information about the design method and options

  • Performance measurements for the filter response, such as the passband cutoff or stopband attenuation, included in the measure method

  • Cost of implementing the filter in terms of operations required to apply the filter to data, included in the cost method

When the filter uses fixed-point arithmetic, the function returns additional information about the filter, including the arithmetic setting and details about the filter internals.

s = info(h) returns filter information in the variable s. You can also provide the optional arguments 'short' and 'long' with this syntax.

Input Arguments

h

One of the following types of filter object or filter System object™:

‘short'

Input string that instructs the function to return basic information about the filter.

‘long'

Input string that instructs the function to return in-depth information about the filter.

Output Arguments

s

Variable for storing filter information.

Examples

Obtain short-format and long-format information about a filter.

>> d = fdesign.lowpass;
>> f = design(d);
>> info(f)
Discrete-Time FIR Filter (real)    
-------------------------------    
Filter Structure  : Direct-Form FIR
Filter Length     : 43             
Stable            : Yes            
Linear Phase      : Yes (Type 1)   

>> info (f)
Discrete-Time FIR Filter (real)    
-------------------------------    
Filter Structure  : Direct-Form FIR
Filter Length     : 43             
Stable            : Yes            
Linear Phase      : Yes (Type 1) 
  
>> info(f,'long')
Discrete-Time FIR Filter (real)                
-------------------------------                
Filter Structure  : Direct-Form FIR            
Filter Length     : 43                         
Stable            : Yes                        
Linear Phase      : Yes (Type 1)               
                                               
Design Method Information                      
Design Algorithm : equiripple                  
                                               
Design Options                                 
DensityFactor : 16                             
MinOrder      : any                            
MinPhase      : false                          
StopbandDecay : 0                              
StopbandShape : flat                           
                                               
Design Specifications                          
Sampling Frequency : N/A (normalized frequency)
Response           : Lowpass                   
Specification      : Fp,Fst,Ap,Ast             
Passband Edge      : 0.45                      
Stopband Edge      : 0.55                      
Passband Ripple    : 1 dB                      
Stopband Atten.    : 60 dB                     
                                               
Measurements                                   
Sampling Frequency : N/A (normalized frequency)
Passband Edge      : 0.45                      
3-dB Point         : 0.46956                   
6-dB Point         : 0.48313                   
Stopband Edge      : 0.55                      
Passband Ripple    : 0.8919 dB                 
Stopband Atten.    : 60.9681 dB                
Transition Width   : 0.1                       
                                               
Implementation Cost                            
Number of Multipliers : 43                     
Number of Adders      : 42                     
Number of States      : 42                     
MultPerInputSample    : 43                     
AddPerInputSample     : 42    

See Also

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