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155.69.2.13: /* Introduction */

2014-02-03T09:09:09Z

Introduction

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	~~Alyson~~ is ~~what my husband enjoys~~ to ~~call me but~~ I ~~don't like when people use my full title~~. ~~My spouse~~ and I ~~live~~ in ~~Kentucky~~. ~~I am really fond~~ of to go to ~~karaoke but I've~~ been ~~using on new things lately~~. ~~Invoicing is what I do~~ for a ~~living but I~~'~~ve usually wanted my own company~~.<br><br>~~Look into my weblog; best psychic readings~~ ([~~http~~://~~cspl~~.~~postech~~.ac.kr/~~zboard~~/~~Membersonly~~/~~144571~~ http://~~cspl~~.~~postech~~.ac.kr])		{{merge\|SINR\|discuss=Talk:THIS PAGE#Merger proposal\|date=September 2013}}


			In [[telecommunications]], the '''carrier-to-noise ratio''', often written CNR or ''C/N'', is the [[signal-to-noise ratio]] (SNR) of a [[modulation\|modulated]] signal. The term is used to distinguish the CNR of the radio frequency [[passband]] signal from the SNR of an analogue [[base band]] message signal after [[demodulation]], for example an audio frequency analogue message signal. If this distinction is not necessary, the term SNR is often used instead of CNR, with the same definition.

			Digitally modulated signals (e.g. [[QAM]] or [[Phase-shift_keying\|PSK]]) are basically made of two [[Continuous_wave\|CW]] carriers (the [[Phase_(waves)#In-phase_and_quadrature_.28I.26Q.29_components\|I and Q]] components, which are out-of-phase carriers) . In fact, the information (bits or symbols) is carried by given combinations of phase and/or amplitude of the I and Q components. It is for this reason that, in the context of digital modulations, digitally modulated signals are usually referred to as carriers. Therefore, the term carrier-to-noise-ratio (CNR), instead of signal-to-noise-ratio (SNR) is preferred to express the signal quality when the signal has been digitally modulated.

			High ''C/N'' ratios provide good quality of reception, for example low [[bit error rate]] (BER) of a digital message signal, or high SNR of an analogue message signal.

			==Definition==
			The carrier-to-noise ratio is defined as the ratio of the received modulated carrier signal [[Power (physics)\|power]] ''C'' to the received noise power ''N'' after the receive filters:
			:<math>
			\mathrm{CNR} = \frac{C}{N}
			</math>.
			When both carrier and noise are measured across the same [[Characteristic impedance\|impedance]], this ratio can equivalently be given as:
			:<math>
			\mathrm{CNR} = \left( \frac{V_C}{V_N} \right) ^2
			</math>,
			where <math>V_C</math> and <math>V_N</math> are the [[root mean square]] (RMS) voltage levels of the carrier signal and noise respectively.

			''C''/''N'' ratios are often specified in [[decibel]]s (dB):
			:<math>
			\mathrm{CNR_{dB}} = 10 \log_{10}\left( \frac {C}{N} \right) = C_{dBm} - N_{dBm}
			</math>
			or in term of voltage:
			:<math>
			\mathrm{CNR_{dB}} = 10 \log_{10}\left( \frac{V_C}{V_N} \right) ^2 = 20 \log_{10}\left( \frac {V_C}{V_N} \right)
			</math>

			The ''C/N'' ratio is measured in a manner similar to the way the [[signal-to-noise ratio]] (''S/N'') is measured, and both specifications give an indication of the quality of a communications channel.

			In the famous [[Shannon–Hartley theorem]], the ''C/N'' ratio is equivalent to the ''S/N'' ratio. The ''C/N'' ratio resembles the [[carrier-to-interference ratio]] (''C/I'', '''CIR'''), and the [[carrier-to-noise-and-interference ratio]], ''C/(N+I)'' or '''CNIR'''.

			== See also ==
			* [[Signal-to-noise ratio]] (SNR or ''S''/''N'')
			* [[Signal-to-interference ratio]] (SIR or ''S''/''I'')
			* [[SINAD]] (ratio of signal-plus-noise-plus-distortion to noise-plus-distortion)
			* [[Eb/N0]] (energy per bit relative to noise power spectral density)
			* [[Es/N0]] (energy per symbol relative to noise power spectral density)
			* [[Carrier-to-receiver noise density]] ''C/''N''<sub>0</sub>

			==References==
			<references/>
			{{unreferenced\|date=February 2008}}

			== External links ==
			* [http://www.cisco.com/en/US/prod/collateral/video/ps8806/ps5684/ps2209/prod_white_paper0900aecd805738f5_ps2217_Products_White_Paper.html Digital Transmission: Carrier-to-Noise, Signal-to-Noise & Modulation Error Ratio]

			{{Noise}}

			[[Category:Noise]]
			[[Category:Engineering ratios]]

en>Helpful Pixie Bot: ISBNs (Build KE)

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ISBNs (Build KE)

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Alyson is what my husband enjoys to call me but I don't like when people use my full title. My spouse and I live in Kentucky. I am really fond of to go to karaoke but I've been using on new things lately. Invoicing is what I do for a living but I've usually wanted my own company.<br><br>Look into my weblog; best psychic readings ([http://cspl.postech.ac.kr/zboard/Membersonly/144571 http://cspl.postech.ac.kr])

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en>Qwertyus: /* Applications */ remove more opinion, and an undated announcement

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155.69.2.13: /* Introduction */

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