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carlyou
Joined: 06 Dec 2004
Posts: 72
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 09 Dec 2004 5:12 Who can tell me what is A-weight filter? |
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| thank you.
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Borber
Joined: 01 Jan 1970
Posts: 1492
Helped: 112
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| 09 Dec 2004 9:06 Re: Who can tell me what is A-weight filter? |
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| Weighting filters are used in audio S/N measurements. Basic shape of filter is inverse to human ear sensitivity characteristic. One of these shapes is A weighting filter (exists allso B, CCIF etc). Idea is to give more weight to frequency components at which ear is more sensitive. On web you can find a lot data about audio weighting filters.
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xwcwc1234
Joined: 21 Jul 2001
Posts: 313
Helped: 5
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| 09 Dec 2004 9:09 Re: Who can tell me what is A-weight filter? |
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| How to simulate the A-weight filter using Hspice ?
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LCI
Joined: 09 Sep 2004
Posts: 8
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| 09 Dec 2004 9:25 Re: Who can tell me what is A-weight filter? |
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using a ideal circuit (R,C,VCVS) to implement the a-weight filter.
However, if i want to measure the a-weight noise in ADC channel,
How to implement this?
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Borber
Joined: 01 Jan 1970
Posts: 1492
Helped: 112
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| 09 Dec 2004 16:38 Re: Who can tell me what is A-weight filter? |
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To simulate weighting filter you must know it's transfer function or equivalent filter circuit. In attechement I put CCIR 468-3 filter circuit where must be added +12.2dB amplifier and weighting curves A and CCIR 468-3. Weighting curve A is usually used with consumer audio products while CCIR is meant for proffesional usage.
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xwcwc1234
Joined: 21 Jul 2001
Posts: 313
Helped: 5
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| 10 Dec 2004 5:21 Re: Who can tell me what is A-weight filter? |
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To Borber,
Thanks.
But this circuit is for CCIR-468 , how to make a A-weighting filter circuit for SPICE simulation ?
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xwcwc1234
Joined: 21 Jul 2001
Posts: 313
Helped: 5
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| 10 Dec 2004 5:23 Re: Who can tell me what is A-weight filter? |
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To Borber,
By the way , I noticed that you got many points (over 1000!). Would ypu like to donate some to me ? Thanks again.
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Borber
Joined: 01 Jan 1970
Posts: 1492
Helped: 112
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| 10 Dec 2004 8:12 Re: Who can tell me what is A-weight filter? |
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| For A curve I do not have transfer function or equivalent circuit. I suppose, filter order and topology should be the same as for CCIR filter. You may try some iterative simulation to get close result but it is rather slow and inaccurate way.
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