down-sampler & up-sampler

[banh]

are they linear system?

 

[kilone]

Yeah, I think they are linear.

 

[Circuit_seller]

Hi,

They are linear because we can use z-transform to show them( this is not why they are linear, but you can accept if we use H(z) so they are linear).

Regards

 

[pimr]

hi,
they are linear but not time invariant.As up sampling and downsampling operators both operate on time they do not affect scaling.
pimr

 

[jetset]

hi,
they are linear but not time invariant.As up sampling and downsampling operators both operate on time they do not affect scaling.
pimr

That's right, these kind of systems are time variant systems, but linear.

 

[van_gift]

LTV vs LTI: linear time variant and linear time invariant

 

[ye.hui]

they are time invariant because if the input signal is delayed a specified time, the output signal will not be delayed the same time.

 

[gnudaemon]

they are time invariant because if the input signal is delayed a specified time, the output signal will not be delayed the same time.

This is called time-variant, not time-invariant

 

[boeysue]

down sampling & up-sampling can be linear or non-linear system..
It depends on your design.

 

[ye.hui]

they are time invariant because if the input signal is delayed a specified time, the output signal will not be delayed the same time.

This is called time-variant, not time-invariant

sorry, it is a clerical error.

 

[gnudaemon]

they are time invariant because if the input signal is delayed a specified time, the output signal will not be delayed the same time.

This is called time-variant, not time-invariant

sorry, it is a clerical error.

Just want to clarify to avoid confusing others.
Pls be careful when posting, 'cos only 2 opposite answers here.

 

[laocai]

of cource it's linear system in theory ,but sampling is time-variant ,so the up/down sampler is linear time variant system

Added after 1 minutes:

of cource it's linear system in theory ,but sampling is time-variant ,so the up/down sampler is linear time variant system

 

[Circuit_seller]

Hi

Upsampling and Downsampling are both Linear in theory and practice.

Regards

 

[somik13]

Any of you guys know how to represent up-sampler & down-sampler in Z domain?