S/N Ratio meaning help

[mariner 0]

What does the S/N ratio mean? Is a higher number better or worse?

 

Thanks for any help.

[spaceman 0]

Signal to noise ratio (s/n) indicates how much "signal," or actual picture information, the camera transmits, as opposed to "noise," which comes across as static. A s/n ratio of 40db indicates that the signal is 100 times the noise, which results in an acceptable picture with some fine grain or snow. 30db results in a poor picture, and 60db produces an excellent picture with no static visible.

[Thomas 0]

And S/N ratios are a logarithmic scale rather then simply additive. If I recall my math correctly, the differance between say 45 db and 48 db is double the image quality.

[blowrabbit 0]

in the real world of cctv cams the best are always 50db > however some that pretend to be 50 db can still be lousy for example the speco indoor dome something like the hr616? says its 50 db but its really poor in picture quality and resolution. in short you get what you pay for as the specos were not more than [$..... cant say] but they were cheep.

[B digital 0]

In theory, the higher the S/N ratio, the higher the quality of the image will be produced. As far as camera spec sheets go, it all depends on what conditions the camera was under when the S/N ratio was measured.

 

As I understand it, an un-weighted signal gives the most accurate measure. Some companies use special filters during testing to improve the S/N ratios of their product. A weighted signal is about 8 db higher than un-weighted signal. So, its no surprise that most manufacturers dont specify whether stated S/N value is weighted or unweighted. If they do, you can be sure their not trying to hide anything.