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dnyberg2

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- Thread starter dnyberg2
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- #1

dnyberg2

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- #2

Zryn

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SNR (dB) = 10 log (Ps / Pn) = Ps (dB) - Pn (dB)

c = B * log10 (1+SNR) / log10 (2)

Does that help?

c = B * log10 (1+SNR) / log10 (2)

Does that help?

- #3

dnyberg2

- 125

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SNR (dB) = 10 log (Ps / Pn) = Ps (dB) - Pn (dB)

c = B * log10 (1+SNR) / log10 (2)

Does that help?

Where did C and B come from?

The top line makes sense but you lost me with the second line...

Thanks

- #4

Zryn

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c = B * log2 (1+SNR) = B * log10 (1+SNR) / log10 (2)

- #5

dnyberg2

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c = B * log2 (1+SNR) = B * log10 (1+SNR) / log10 (2)

Yes. I'm trying to understand how to calculate the S/N ratio for that application.

- #6

Zryn

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SNR (dB) = 10 log (Ps / Pn) = Ps (dB) - Pn (dB)

This is how you generically figure out the SNR from the power (W or dB).

c = B * log2 (1+SNR) = B * log10 (1+SNR) / log10 (2)

This is Shannons formula, which wasn't expressly written down in the original post, and is just there to make sure we're talking about the same thing.

Does that clarify everything?

- #7

dnyberg2

- 125

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This is how you generically figure out the SNR from the power (W or dB).

This is Shannons formula, which wasn't expressly written down in the original post, and is just there to make sure we're talking about the same thing.

Does that clarify everything?

Sure. So c is channels and b is bandwidth?

- #8

Zryn

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c = Maximum theoretical channel capacity (bits/second). This may not be achievable in reality.

B = Bandwidth (Hz)

Actually, all this and more can be found at http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem" [Broken]

B = Bandwidth (Hz)

Actually, all this and more can be found at http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem" [Broken]

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- #9

dnyberg2

- 125

- 2

c = Maximum theoretical channel capacity (bits/second). This may not be achievable in reality.

B = Bandwidth (Hz)

Actually, all this and more can be found at http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem" [Broken]

Thanks for your patience and wisdom. Any idea where I can find a guide to the best modulation scheme that can transmit the highest bit-rates using the least bandwidth with the best spectral density? I find that GFSK looks sexy but still the bandwidth is still relatively substantial and the currently available chipsets are VERY power hungry! I am confined to the ISM band for my application. The present solution is very easy on battery power but a spectral hog. (BAD FCC) My present bit-rate is over 1mbps using a crude on / off keying approach of a very low power class D amplifier...

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