Bias (bias_l)

Adds a fixed bias to all input sample values.

Design

The mathematical representation of the implementation is given in (81).

(81)\[y[n] = B + x[n]\]

In (81):

  • \(x[n]\) is the input values.

  • \(y[n]\) is the output values.

  • \(B\) is the bias value.

A block diagram representation of the implementation is given in Figure 130:.

Block diagram outlining bias implementation.

Figure 130: Bias implementation.

Interface

<?xml version="1.0"?>
<componentspec>
  <property name="bias" type="long" writable="true" default="0" description="Bias value added to input values."/>
  <port name="input" producer="false" protocol="long_timed_sample-prot"/>
  <port name="output" producer="true" protocol="long_timed_sample-prot"/>
</componentspec>

Ports

Inputs:

  • input: Primary input samples port.

    • Protocol: long_timed_sample-prot

    • Optional: False

Outputs:

  • output: Primary output samples port.

    • Protocol: long_timed_sample-prot

    • Optional: False

Opcode Handling

A bias is only added to values in sample opcode messages. All other opcode messages received are passed through this component without any effect.

Properties

  • bias: Bias value added to input values.

    • Type: long

    • Access:

      • Parameter: False

      • Writable: True

      • Initial: False

      • Volatile: False

    • Default value: 0

Implementations

Example Application

<?xml version="1.0"?>
<application done="file_write">
  <instance component="ocpi.core.file_read" connect="bias_l">
    <property name="filename" value="input.bin"/>
  </instance>
  <instance component="ocpi.comp.sdr.math.bias_l" connect="file_write">
    <property name="bias" value="5"/>
  </instance>
  <instance component="ocpi.core.file_write">
    <property name="filename" value="output.bin"/>
  </instance>
</application>

Dependencies

The dependencies to other elements in OpenCPI are:

  • None

There is also a dependency on:

  • ieee.std_logic_1164

  • ieee.numeric_std

Limitations

Limitations of bias_l are:

  • None.

Testing

Tested platforms: None

Component testing not completed.