Signal Decimation

Summary

Doc_BoxAlgorithm_SignalDecimation.png
  • Plugin name : Signal Decimation
  • Version : 1.0
  • Author : Yann Renard
  • Company : INRIA
  • Short description : Reduces the sampling frequency to a divider of the original sampling frequency
  • Documentation template generation date : Dec 30 2016

Description

No pre filtering applied - Number of samples per block have to be a multiple of the decimation factor

This box reduces the sampling frequency of an input signal the easy way. It is different of the existing Downsampling box in the sense that there is no pre-filtering and that you can not choose an arbitrary sampling frequency. Thus you will have to pre-filter the input signal with the Temporal filter box for example. The new sampling frequency will be an exact divider of the source signal sampling frequency. For instance, if your input sampling frequency is 1000Hz, you are allowed to divide that frequency by 2 or 4 but you can't divide it by 3. See section Examples for a detailed example of what can be done.

Inputs

1. Input signal

The input signal.

  • Type identifier : Signal (0x5ba36127, 0x195feae1)

Outputs

1. Output signal

The decimated signal.

  • Type identifier : Signal (0x5ba36127, 0x195feae1)

Settings

1. Decimation factor

The sampling rate divider. At each chunk reception, 1 sample among n of the input signal will be sent to the output signal.

  • Type identifier : Integer (0x007deef9, 0x2f3e95c6)
  • Default value : [ 8 ]

Examples

Suppose you have a signal with a sampling rate of 1000Hz streamed with 32 samples per buffer that you want to downsample to 100Hz. Downsampling this signal to 100Hz will require that you low-pass filter the signal to at most 50Hz to avoid bad results. Additionally, Changing the epoch sizes using a the Time based epoching box and configuring it e.g. for epochs of 0.1s every 0.1s will cause this box to output 10 samples sized buffers.

Miscellaneous