(I) Downsample

Reduce the sampling rate by an integer multiple

Reduce the sampling rate by an integer multiple

- syntax

y =downsample (x, n)

y =downsample (x, n, phase) y =downsample (x, n) reduces the sampling rate of x by retaining the first sample and then the NTH sample after the first sample. If x is a matrix, the function treats each column as a separate sequence. Y = Downsample (x, n, phase) specifies the number of samples for the sampling sequence under offset. Example 1:

reduces the sampling rate of the sequence by a factor of 3. x = [1 2 3 4 5 6 7 8 9 10];

y =downsample (x, 3)

y = 1×4 1 4 7 10 example 2: reduce the sampling rate of the sequence by 3 times and increase the phase offset by 2. That is to offset two Numbers backward from the first number for downsampling y =downsample (x, 3, 2)

y = 1×3 3 6 9

x1 = [1 2 3 4 5 6 7 8 9];

y =downsample(x1,3,1) y = 2 5 8

example 3:

reduces the sampling rate of the matrix by 3 times. X = [1 2 3;

4 5 6;

7 8 9;

10, 11 12];

y =downsample (x, 3)

y = 2×3 12 3

10 11 12 input parameters

x — input array

vector | matrix

input array, specified as a vector or matrix. If x is a matrix, the function treats the columns as independent channels. Example: Cosine (PI/4 * (0:15 9)) + RANDn (1,160) specifies the sine curve plus the White Gaussian noise. Example: cos (PI./ [4; 2] * (0:15 9)) ‘+ randn (160,2) specifies a two-channel sine wave. Data type: single | double

complex number support: is

n – down sampling coefficient

positive integer

under sampling factor, specified as a positive integer. Data type: single | double

phase – offset

(default) | positive integer

offset, specified as a positive integer between 0 and n-1. Data type: single | double output parameter

y – down sampling array

vector | matrix

down sampling array, returned as a vector or matrix.

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