DC Block

Overview

A DC blocker is a high-pass filter which attenuates frequencies below the signal’s lowest frequency of interest. Eliminating the DC offset from a signal allows the signal to be analyzed or processed more effectively in subsequent stages.

dc_block is an implementation of a DC blocker based on Julius O. Smith’s document Introduction to Digital Filters.

Include

#include <q/fx/dc_block.hpp>

Declaration

struct dc_block
{
               dc_block(frequency f, float sps);

   float       operator()(float s);
   float       operator()() const;
   dc_block&   operator=(float y);
   void        cutoff(frequency f, float sps);
};

Expressions

Notation

bk, a, b

Objects of type dc_block.

f

Object of type frequency representing the cutoff frequency.

sps

Floating point value representing samples per second.

s

Input sample.

Constructor

Constructors and Assignment

Expression Semantics

dc_block(f, sps)

Construct a dc_block with specified cutoff frequency, f, and samples per second sps.

dc_block(b)

Copy construct a dc_block from b.

a = b

Assign b to a.

a = s

Set the latest result to s.
C++ brace initialization may also be used.
Expression Semantics Return Type

bk()

Return the latest result.

float

bk(s)

Remove DC from the input sample s.

float

Mutators

Expression Semantics Return Type

bk.cutoff(f, sps)

Set the cutoff frequency given frequency f, and samples per second sps.

void