Day 1 Flashcards
How do you convert a real number into a dB?
LOG the number, x 10
How do you convert a dB into a real number?
Divide by 10, put number to power of 10
What dB value would equate to half the power?
-3
What dB power would equate to double?
3
What is a decibel?
Logarithmic scale for a huge numerical range
What is Bandwidth?
The difference between upper and lower frequencies of the signal. Too small will cut off pulse, too large will allow more noise.
What is Bandwidth?
The difference between upper and lower frequencies in a continuous set of frequencies typically measured in Hz. Too small will cut off pulse, too large will allow more noise.
What is signal to noise ratio? SNR
Shown in dB, it is a measure of a radars ability to see targets in the presence of noise.
SNR > 1 = detectable signal
SNR
What are the sources of noise in a system?
Internal
External
What are the internal sources of noise in a system?
Equipment, transmission and antenna
What are the external sources of noise?
Interference, Jamming, Weather and Ground clutter
What is EW broken into?
EA - Jamming, deception & neutralisation
ES - SIGINT - COMINT/ELINT & Warning
EP - EMCON, masking, hardening, WRM
What is an electronic wave?
Is a sinusoidal wave that consists of electric (E) and magnetic (H) fields always at 90 degrees to each other. No need for a medium, obey same laws of wave motion.
What is the speed of light?
3 x 10^8 metres per second
162,000 nm per second
186,000 miles per second
What does radar stand for?
Radio detection and ranging
What is frequency?
The number of cycles that occur in 1 second in Hz