What's the correct way to align two signals downsampled at 10 Hz?

1. How do you downsample a signal?
2. How do you align two signals in Matlab?
3. Why do we downsample a signal?

How do you downsample a signal?

y = downsample( x , n ) decreases the sample rate of x by keeping the first sample and then every n th sample after the first. If x is a matrix, the function treats each column as a separate sequence. y = downsample( x , n , phase ) specifies the number of samples by which to offset the downsampled sequence.

How do you align two signals in Matlab?

[ xa , ya ] = alignsignals( x , y ) estimates the delay D between the two input signals x and y , and returns the aligned signals xa and ya . The function estimates the delay using cross-correlation. If y is delayed with respect to x , then D is positive and x is delayed by D samples.

Why do we downsample a signal?

(1) To make a digital audio signal smaller by lowering its sampling rate or sample size (bits per sample). Downsampling is done to decrease the bit rate when transmitting over a limited bandwidth or to convert to a more limited audio format.