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banh
Joined: 16 Dec 2004
Posts: 472
Helped: 12
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 24 Jan 2005 6:10 down-sampler & up-sampler |
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| are they linear system?
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kilone
Joined: 19 Mar 2004
Posts: 40
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| 24 Jan 2005 7:19 down-sampler & up-sampler |
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| Yeah, I think they are linear.
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Circuit_seller
Joined: 23 Sep 2002
Posts: 409
Helped: 14
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| 24 Jan 2005 8:22 Re: down-sampler & up-sampler |
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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
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pimr
Joined: 19 May 2004
Posts: 81
Helped: 6
Location: India
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| 24 Jan 2005 14:00 Re: down-sampler & up-sampler |
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hi,
they are linear but not time invariant.As up sampling and downsampling operators both operate on time they do not affect scaling.
pimr
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jetset
Joined: 17 Jun 2004
Posts: 132
Helped: 9
Location: Panama
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| 26 Jan 2005 4:47 Re: down-sampler & up-sampler |
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| pimr wrote: |
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.
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van_gift
Joined: 11 Jan 2005
Posts: 26
Helped: 1
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| 01 Feb 2005 17:05 down-sampler & up-sampler |
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| LTV vs LTI: linear time variant and linear time invariant
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ye.hui
Joined: 20 Dec 2004
Posts: 15
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| 03 Feb 2005 3:16 Re: down-sampler & up-sampler |
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| they are time invariant because if the input signal is delayed a specified time, the output signal will not be delayed the same time.
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gnudaemon
Joined: 16 Sep 2004
Posts: 35
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| 04 Feb 2005 3:44 Re: down-sampler & up-sampler |
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| ye.hui wrote: |
| 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
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boeysue
Joined: 23 Dec 2004
Posts: 190
Helped: 3
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| 04 Feb 2005 17:48 Re: down-sampler & up-sampler |
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down sampling & up-sampling can be linear or non-linear system..
It depends on your design.
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ye.hui
Joined: 20 Dec 2004
Posts: 15
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| 05 Feb 2005 3:53 Re: down-sampler & up-sampler |
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| gnudaemon wrote: |
| ye.hui wrote: |
| 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.
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gnudaemon
Joined: 16 Sep 2004
Posts: 35
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| 05 Feb 2005 11:23 Re: down-sampler & up-sampler |
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| ye.hui wrote: |
| gnudaemon wrote: |
| ye.hui wrote: |
| 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.
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laocai
Joined: 30 Dec 2003
Posts: 20
Location: china
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| 06 Feb 2005 12:02 Re: down-sampler & up-sampler |
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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
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Circuit_seller
Joined: 23 Sep 2002
Posts: 409
Helped: 14
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| 06 Feb 2005 15:59 Re: down-sampler & up-sampler |
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Hi
Upsampling and Downsampling are both Linear in theory and practice.
Regards
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somik13
Joined: 15 Feb 2007
Posts: 17
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| 09 May 2008 21:41 Re: down-sampler & up-sampler |
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| Any of you guys know how to represent up-sampler & down-sampler in Z domain?
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