SEW Day 5 Flashcards
(13 cards)
compares the level of desired signal to the level of background noise
Signal-to-Noise Ratio (SNR)
rate at which a transmitted segment of data is received with incorrect bits as compared to the original message.
Bit Error Rate (BER)
Bit Error Rate (BER)
___ Signal Strength
___ Noise Levels
___ data rates (more chances for ___)
Low Signal Strength
High Noise Levels
High data rates (more chances for errors)
a common means of encoding data to determine if any errors have been introduced to the message through channel noise, interference, or other source
Error Detection
a method of adding redundant information to a data stream that allows for identification and correction of errors, and thus reduces or eliminates the need for retransmission
Forward Error Correction (FEC)
Resiliency through redundancy
Error Detection
FEC is implemented in both the _____ to encode the data, and the _____ to recover lost data from a noisy communication channel
- transmitter
- receiver
The FEC system sends an _____ along with the data. The receiver never sends any message back to the transmitter, but decodes what is received into the “most likely” data.
error correction code (ECC)
Common FEC
1/2, 3/4, 7/8
½ = 1 data bit in, 2 bits come out / ¾ = 3 data bits in, 4 bits come out…
Identify tradeoffs between Bandwidth (BW) usage and FEC schemas
- 1/2 costs more Bandwidth, but ensures data is able to be corrected by sending the most parity bits
- 7/8 has faster data rates but is more prone to errors.
FEC ___ the amount of BW required
increases
If you have bandwidth to spare, use a ___ to increase the chance that data is being received the way the transmitter intended.
higher FEC
If you have ____ to spare, use a higher order modulation scheme.
power
