Signal Processing Toolbox

downsample

Decrease the sampling rate of the input signal

Syntax

• y = downsample(x,n)
  y = downsample(x,n,phase)
  

Description

y = downsample(x,n) decreases the sampling rate of x by keeping every n^th sample starting with the first sample. x can be a vector or a matrix. If x is a matrix, each column is considered a separate sequence.

y = downsample(x,n,phase) specifies the number of samples by which to offset the downsampled sequence. phase must be an integer from 0 to n-1.

Examples

Decrease the sampling rate of a sequence by 3:

• x = [1 2 3 4 5 6 7 8 9 10];
  y = downsample(x,3)
  y =
      1    4    7    10
  

Decrease the sampling rate of the sequence by 3 and add a phase offset of 2:

• y = downsample(x,3,2)
  y =
      3    6    9
  

Decrease the sampling rate of a matrix by 3:

• x = [1 2 3; 4 5 6; 7 8 9; 10 11 12];
  y = downsample(x,3);
  x,y
  x =
      1    2    3
      4    5    6
      7    8    9
     10   11   12
  y = 
      1    2   3
     10   11   12
  

See Also

decimate, interp, interp1, resample, spline, upfirdn, upsample

diric

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