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vivian0412
Joined: 24 Aug 2004
Posts: 1
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 24 Aug 2004 6:57 delta modulation and sigma delta modulatiom between differe |
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please help me...
I want to know delta modulation and sigma delta modulatiom between different??
IF you have answer can send e-mail :leeza200(at)ms56.hinet.net
thanks
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eda4you
Joined: 17 Sep 2002
Posts: 283
Helped: 17
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24 Aug 2004 9:47 Re: delta modulation and sigma delta modulatiom between diff |
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| In contrast to sigma-delta modulators, delta modulators have their integrator(s) in the feedback path and not in it forward path ( input - integrators - adc) . Therefore, no noise-shaping is done. Hence, it isn't usefull for oversampling converters.
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Btrend
Joined: 26 Dec 2003
Posts: 424
Helped: 55
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25 Oct 2004 7:47 Re: delta modulation and sigma delta modulatiom between diff |
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u can check the topic in section 5 & 6 of the attachment 
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piao
Joined: 12 Feb 2003
Posts: 223
Helped: 7
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26 Oct 2004 15:26 delta modulation and sigma delta modulatiom between differe |
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the difference is in a lot of communcation book since delta modulator and sigma delta modulator are all from communication.
you can refer to those books.
the description in those communication book are clear.
Good Luck!
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devrimaksin
Joined: 13 Oct 2004
Posts: 93
Helped: 9
Location: Dallas, Texas, USA
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26 Oct 2004 16:57 delta modulation and sigma delta modulatiom between differe |
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In delta modulator,
the feedback loop try to minimize the
error, the variation of the input signal, (for example,
assume that at t=t0, input is V0 and, t=t1 your input
is V1, then the output will be related to V1-V0). So the system try to generate the differences. For low frequency systems, this is quirte advantageous, because the differences can be very small therefore
the dyanmic range requirement is reduced.
Now in sigma delta modulator, the modulator integrate this differences which is equivalent to filtering which improve the signal to noise ratio of the system. Check the definition of the signal transfer function and noise transfer function, it will make it clearer
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