11827477
Description
Flashcards by Pascal Jud, updated more than 1 year ago
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Created by Pascal Jud
over 6 years ago
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| Question | Answer |
| 1. OTN: Name, Concept & Components | Optical transport network Elements are connected by a fiber Tx, Multiplexer, Channel, Rx, switches |
| 2. Path and conversion steps of information through OTN | |
| 3. Forward Error Correction (FEC) | Used in Tx & Rx Adds some redundancy in Tx to signal for error detection & correction in Rx |
| 4. ADC: Name, Steps | Analog to digital conversion 1. Sampling the analog signal at F_s 2. Quantization of the analog amplitude into M quantized levels 3. Coding: assign every level a value & convert it into a digital signal |
| 5. Sampling theorem | The Theorem states that a bandwidth-limited signal can be reconstructed completely if it is sampled once by a complex value or twice per symbol. |
| 6. Procedure to reconstruct an analog waveform from its samples | 1. ideal low pass filter 2. (real) Sampling at Nyquist rate 3. Reconstruction |
| 7. Concept of aliasing | If undersampling happens, i can happen that frequencies cannot be distiguished properly. All frequencies outside of the Nyquist critical sampling frequencies are falsely translated into the Nyquist sampling range |
| 8. Reason for limitation to 2^m of amount of coding levels | m: amount of bits Each coding level is mapped to a binary number which leads to the limitation. |
| 9. What does the frequency response of a channel describe? | Difference of magnitude and phase between in- & output |
| 10. Channel capacity | Maximum rate at which bits can be transferred reliably ( BER = 10^-3) |
| 11. Elements of Shannon channel capacity | Bandwidth, Signal power, Noise power |
| 12.1 Spectral Efficiency | Maximum number of bits per bandwidth that can be transmitted |
| 12.2 Describe the red area | No longer reliable communication |
| 13. Difference between symbol and bit rate | A symbol can have more than one bit. --> nR_s = R_b |
| 14. Advantages of fiber telecommunication compared to other wired communication | higher bandwidth attenuation much lower cheaper fibers than cables |
| 15. Bandwidth limitation of an optical fiber | IR absorption OH absorption peak Rayleigh scattering |
| 16. Nonlinear Shannon limit | breakdown of the fiber due to too much power |
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