Signal-to-Noise, Carrier-to-Noise, EbNo

Broadcasted on 11/18/2010

Signal-to-Noise, Carrier-to-Noise, EbNo - Wolfgang Damm

Wolfgang Damm
Dir. of Product Marketing

Data transmission is often conducted under very difficult circumstances; weak signals that transport high data rates within an unfavorable noise environment have to be recognized by receivers. Furthermore, data streams have to be transmitted reliably and with low BER. Designers, developers and system engineers have to take less-than-ideal circumstances in consideration when they design their circuits or monitor their system. The measurements discussed in this webinar are relevant for Satellite applications, Cable TV, telecommunications and as well for other RF technologies. The webinar is designed for an audience interested in learning about optimizing signal and data transmission and how to utilize modern test equipment.

Topics

  • Measurement Environment
  • Ratios: S/N, C/N, C/No, C/I, EbNo
  • Shannon Limit
  • Error Correction
  • BER and Coding schemes
  • Noisecom CNG-EbNo

Webinar Q&A

Below are questions we received during the webinar. If you have any additional questions, email us.

What is the highest frequency a CNG-EbNo can process?

We have CNG-EbNos in the pricelist as standard units up to 22 GHz – but this is not the limitation.

Noisecom has always been a good choice when customization is required. We can build systems with higher frequencies that 22 GHz, different flatness, you name it. If you need a specific configuration please call the factory or your next Noisecom representative. We will discuss the requirements with you and provide a tailored solution.

What is the Boltzmann’s constant?

Someone here wants to calculate if the formulas are correct... The Boltzmann’s constant is:
1.38065 x10 E-23 J/K

What is the difference between signal power and carrier power?

There are different views what is what, but basically they are want to explain the same.

Some use the term “signal” for base band frequencies and “carrier” for RF frequencies, but I tend to favor the explanation that the term “signal” is used for analog modulated signals while “carrier” is used in the digital modulated word.

What is the substitution method?

Noisecom uses very accurate measurement devices - in this case a power meter. But the substitution method eliminates the effects of any non-linearity in the measuring device so the result is even more accurate.

How does it work?
The First step is setting the signal and the noise to the same power level at the power meter input.

Then the noise power is then offset by the desired ratio.
Effects such as thermal drift becomes negligible since the noise and the power are measured within a very short time frame.

Are EbN0 measurements performed using base band or carrier frequencies?

Both ways are possible. EbN0 is a unitless ratio that applies equally to both, baseband and carrier measurements. EbNo allows comparing effectiveness of modulation schemes, so what is important to compare “apples with apples. A baseband signal must be compared with another baseband signal, and the same applies when using carriers. Since baseband frequencies are lower in frequency, they are obviously easier to handle. Because of this, many users prefer to use baseband frequencies for their EbN0 measurements.