When the tiger inside me make noise.

the carrier-to-noise ratio, often written CNR or C/N, is the signal-to-noise ratio (SNR) of a 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.

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

Bit error: In data tranmission pariance, this is the measure of the number of error expected in a data link.

                                                 -6

 For example : a BER of 1x10

Means one error in each one million bits transmited

C/N : Carrier-to-noise ratio. The ratio of the receivedcarrier power and the noise power in given bandwith, expressed in DB. This is figured directly related to G/T and S/N;and in video signal, the higher the C/N, the better the received picture will be (Not to be confused with C/No).

C/No.: Carrier-to-Noise Density. Similar to C/N except that no related to the noise in one hertz of bandwidth.

dB : Decibel. A term that express the ratio power levels used to indicaste gains or losses in a system. Also used to express absolute power levels  such as dBm  or dBW. The formular ratio : where P1 and P2 are the power levels :

              

               [ P_1 ]

10 log   {  ------- } dB

        10 {  P_ 2 ]

10 dB = a power ratio of 10

20 dB = a power ratio of 100

30 dB = a power ratio of 1,000

40 dB = a power ratio of 10,000

A power ratio expressed as a negative value,e.g.,

ratios are often specified in decibels (dB):

dB, indicates a less than a gain.

To live the physicians life, it’s a new doctrine what so ever, Solely for the value of lives on earth by thyself. Even though the noise density ratio : error is less than one/a million it is obviously not the accident which  present the spirit of fairy tale by life itself.