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Author Topic: Bits per bin and SNRM difference  (Read 471 times)

Weaver

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Bits per bin and SNRM difference
« on: August 24, 2020, 02:20:12 PM »

Question: In DSL, if you improve the SNR on a tone by x dB so as to get a 1 bit increase in bit-loading, what is x ?
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burakkucat

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Re: Bits per bin and SNRM difference
« Reply #1 on: August 24, 2020, 04:15:16 PM »

I presume that you are asking about the absolute SNR and not the SNRM for a particular frequency?

It's a good question and I feel there must be some "rule of thumb" (or paw) which would allow an estimate to be made.

I suspect that either ejs or Kitz may be able to assist . . .
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digbey

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Re: Bits per bin and SNRM difference
« Reply #2 on: August 24, 2020, 04:56:02 PM »

https://kitz.co.uk/adsl/adsl_technology.htm

~ Bit Loading
  • If the signal is good then 15 bits (maximum) can be allocated to that tone.
  • Each 3dB of SNR equates to 1 bit (of data),
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burakkucat

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Re: Bits per bin and SNRM difference
« Reply #3 on: August 24, 2020, 05:36:43 PM »

  :thumbs:  Thank you. That is what I could not fully recall. Team work prevails, once again.  :)
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Weaver

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Re: Bits per bin and SNRM difference
« Reply #4 on: August 24, 2020, 08:29:03 PM »

Thanks! Measurements taken from SNR and bits-per-bin graphs suggested 3dB to me, but I wanted another opinion. Thanks to Kitz also.
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4candles

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Re: Bits per bin and SNRM difference
« Reply #5 on: August 24, 2020, 10:52:41 PM »

Interesting parallel - that 3db is generally accepted as the smallest difference in level that is easily heard by most people listening to speech or music.
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For every complex problem there is an answer that is clear, simple, and wrong.

Weaver

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Re: Bits per bin and SNRM difference
« Reply #6 on: August 24, 2020, 11:49:45 PM »

That is what I have read too. Indeed, an interesting point. Approximately double the power.
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