Comparision of Transmission lines
Table 1: Comparison of Transmission Cable Types
| Feature | Twisted Pair Cable | Coaxial Cable | Optical Fiber |
|---|---|---|---|
| Signal Transmission | Electrical signals are transmitted through metallic conductors. | Electrical signals are transmitted through the inner conductor. | Information is transmitted as light through a glass or plastic fiber. |
| Noise Immunity | Relatively low; susceptible to electromagnetic interference. | Higher than twisted pair because of its shielding structure. | Very high; optical signals are largely immune to electromagnetic interference. |
| Effect of Magnetic Fields | Can be affected by external electromagnetic fields. | Better protected from external interference because of its shielding. | Unaffected by electromagnetic and magnetic fields. |
| Relative Cost | Low-cost transmission medium. | Moderate cost. | Higher equipment and installation cost. |
| Bandwidth | Relatively low to moderate, depending on cable category and application. | Moderate to high bandwidth. | Very high bandwidth. |
| Attenuation | Relatively high, especially over long distances. | Lower than twisted pair for many applications. | Very low attenuation, enabling long-distance transmission. |
| Installation | Easy and simple to install. | Relatively easy to install but less flexible than twisted pair. | More complex and requires specialized handling and termination. |
Table 2: Comparison of Cable Characteristics
| Characteristic | UTP | STP | Coaxial Cable | Fiber Optic Cable |
|---|---|---|---|---|
| Typical Data Rate | Depends on category; commonly used from 10 Mbps to multi-Gbps Ethernet. | Depends on category; supports high-speed Ethernet applications. | Depends on cable design and application. | From high-speed network links to extremely high-capacity optical systems. |
| Typical Maximum Segment Length | Typically up to 100 m for Ethernet copper links. | Typically up to 100 m for Ethernet copper links. | Depends strongly on cable type, frequency, and application. | Typically several kilometers or more, depending on fiber type and optical system. |
| Interference Immunity | Relatively low compared with shielded and optical media. | Better than UTP because of the additional shielding. | Good because the outer conductor provides electromagnetic shielding. | Excellent immunity to electromagnetic interference. |
| Installation Cost | Low. | Higher than UTP. | Moderate. | Higher because specialized components and installation techniques may be required. |
| Flexibility | Highly flexible and easy to route. | Less flexible than UTP because of the shielding. | Less flexible and generally thicker than twisted pair. | Lightweight and flexible, but must be handled carefully to avoid excessive bending. |
| Security | Lower physical security against signal interception. | Better physical shielding, but still susceptible to electrical interception. | Better shielding than twisted pair, but electrical signals can still be intercepted. | High resistance to electromagnetic interception and difficult to tap without physical access. |
Table 3: Attenuation and Near-End Crosstalk of Twisted Pair Cables
| Frequency (MHz) | Attenuation (dB per 100 m) | Near-End Crosstalk (dB) | ||||
|---|---|---|---|---|---|---|
| Category 3 UTP | Category 5 UTP | 150-ohm STP | Category 3 UTP | Category 5 UTP | 150-ohm STP | |
| 1 | 2.6 | 2.0 | 1.1 | 41 | 62 | 58 |
| 4 | 5.6 | 4.1 | 2.2 | 32 | 53 | 58 |
| 16 | 13.1 | 8.2 | 4.4 | 23 | 44 | 50.4 |
| 25 | — | 10.4 | 6.2 | — | 41 | 47.5 |
| 100 | — | 22.0 | 12.3 | — | 32 | 38.5 |
| 300 | — | — | 21.4 | — | — | 31.3 |
Table 4: Transmission Characteristics of Different Media
| Transmission Medium | Frequency Range | Typical Attenuation | Typical Delay | Typical Repeater Spacing |
|---|---|---|---|---|
| Twisted Pair with Loading | 0 to 3.5 kHz | 0.2 dB/km at 1 kHz | 50 µs/km | Approximately 2 km |
| Multi-Pair Twisted Cable | 0 to 1 MHz | 0.7 dB/km at 1 kHz | 5 µs/km | Approximately 2 km |
| Coaxial Cable | 0 to 500 MHz | 7 dB/km at 10 MHz | 4 µs/km | Approximately 1 to 9 km |
| Optical Fiber | 186 to 370 THz | 0.2 to 0.5 dB/km | 5 µs/km | Approximately 40 km |
Table 5: Fiber Optic Transmission Characteristics
| Wavelength Range (nm) | Frequency Range (THz) | Band | Fiber Type | Typical Application |
|---|---|---|---|---|
| 820 to 900 | 366 to 333 | 850 nm region | Multimode | LAN and short-distance communication |
| 1280 to 1350 | 234 to 222 | S-band | Single-mode | Optical communication systems |
| 1528 to 1561 | 196 to 192 | C-band | Single-mode | Long-distance communication and WDM |
| 1561 to 1620 | 192 to 185 | L-band | Single-mode | Long-distance communication and WDM |