Block DC component
Signal Operations
dspsigops
The DC Blocker block removes the DC component of the input signal.
The DC Blocker dialog box changes based on how the DC offset is estimated.
The dialog box for the IIR
method is shown below.
The dialog box for the FIR
method is shown below.
The dialog box for the CIC
method is shown below.
The dialog box for the Subtract mean
method is shown
below.
Specify the algorithm used for estimating the DC offset. Select from the following:
IIR
uses a recursive estimate based on a narrow, lowpass
elliptic filter. This algorithm typically uses less memory than FIR and is more
efficient.
FIR
uses a nonrecursive, movingaverage estimate. This
algorithm typically uses more memory than IIR and is less efficient.
CIC
uses a lowpass filter that does not employ any
multipliers. If the algorithm is CIC
, then fixedpoint data must
be input to the DC Blocker.
Subtract mean
computes the means of the columns of the input
matrix and subtracts the means from the input. This method does not retain state between
inputs. For example, if the input is [1 2 3 4; 3 4 5 6]
, then the
DC Blocker block in Subtract mean
mode outputs
[1 1 1 1; 1 1 1 1]
.
Specify the normalized filter bandwidth as a real scalar greater than 0 and less than 1.
The DC Blocker uses this parameter only when the estimation algorithm is set to
IIR
or CIC
.
Specify the filter order as an integer greater than 3. The DC Blocker uses
this parameter only when the estimation algorithm is set to
IIR
.
Specify, as a positive integer, the number of samples to use when the estimation
algorithm is set to FIR
.
Opens the fvtool
and displays the magnitude response of the
DC Blocker. The response is based on the block parameters. Changes made to
these parameters update fvtool
.
To update the magnitude response while fvtool
is running, modify the
block parameters and click Apply.
Select the simulation type from the following:
Code generation
(default)
Interpreted execution
This block implements the algorithm, inputs, and outputs described on the dsp.DCBlocker
reference page. The object properties correspond to the block
parameters.
Port  Supported Data Types 

Input 

Output 

[1] Nezami, M., “Performance Assessment of Baseband Algorithms for Direct Conversion Tactical Software Defined Receivers: I/Q Imbalance Correction, Image Rejection, DC Removal, and Channelization”, MILCOM, 2002.