What is Signal to Noise Ratio exactly?

Replies

• 

  Anoop Mathew

  Sanyam Khurana

  Topic explains it all, we have different S/N ratio for different type of signals, but what does this actually mean/imply in real world scenarios?

  There are different types of signals that are in use, and as you mentioned there are different Signal to Noise ratios for each signal.
  
  In Communication, the 'clarity' of voice output obtained at the receiver's end will depend on the least noise(distortion) in the background. This is the reason why you need to either boost the signal strength or reduce the noise while receiving an audio packet - incase the audio packet has more noise.
  
  Of-course better clarity is preferred by everyone during communication.
• 

  Sanyam Khurana

  Anoop Mathew

  There are different types of signals that are in use, and as you mentioned there are different Signal to Noise ratios for each signal.
  
  In Communication, the 'clarity' of voice output obtained at the receiver's end will depend on the least noise(distortion) in the background. This is the reason why you need to either boost the signal strength or reduce the noise while receiving an audio packet - incase the audio packet has more noise.
  
  Of-course better clarity is preferred by everyone during communication.

  So, S/N ratio should be higher for better communication, right?
• 

  Anoop Mathew

  Sanyam Khurana

  So, S/N ratio should be higher for better communication, right?

  Yes. But generally analog devices(your amplifiers, cassette players, etc) would have less S/N ratio compared to digital components (such ad DVD players). The goal is to keep the noise lower at any cost. Different situations would call for different signal strengths which are measured in decibels. So S/N ratio being higher is not the only criteria to be considered to measure the sound quality.
• 

  Harshad Italiya

  Let me explain you something with example.
  S/N ratio is basically ratio of Wanted signal to unwanted signal.
  Now for example Your mobile is transmitting a signal based on the voice recorded by mic. Now the antenna which used to convert this voice signal into RF generates wanted voice signal as well as it generates some unwanted noise also.
  So this ratio is called Signal to Noise ratio.
  
  Normally SN ratio is related to Antenna mostly as it used to generate signals.
• 

  RachaelP

  Harshad Italiya

  S/N ratio is basically ratio of Wanted signal to unwanted signal.

  This is correct but your example isn't strictly correct as mobile phones don't transmit the audio directly as an audio signal these days, it's digitized, encoded and encrypted and sent as digital packets over the mobile network. These digital packets are quite tolerant to noise without the digitized signal getting degraded so they can cope with a relatively low SNR and the audio will still be quite acceptable. Note than mobile phone call quality is designed to be the lowest acceptable quality anyway so they can cram as many channels in the available bandwidth as possible.
  
  On the other hand, digital audio from say a CD player, passes into a DAC and the resulting analogue output goes into a pre-amp and then a power amp and to the speakers. The quality of the analogue audio signal as it passes through the various parts of the system must be maintained at a very high SNR otherwise in an audio system such as this the quality of the music would be noticeably degraded.
  
  I hope this helps.
  
  Best Regards,
  
  Rachael