Physics · Ch 15 — Communication Systems
Bandwidth of Transmission Medium
15.5
Bandwidth of Transmission Medium
Bandwidth of Transmission Medium
Just as a signal occupies a certain bandwidth, a transmission medium can only carry a certain bandwidth.
- Wire media, such as coaxial cable, offer a usable bandwidth of roughly 750 MHz and are normally operated at frequencies below 18 GHz.
- Free space (radio-wave propagation) offers an extremely wide range, from a few hundred kHz to a few GHz. Because this range must be shared by many services, it is divided up and allocated internationally, as summarised below.
Table 15.2 - Some Important Wireless Communication Frequency Bands
| Service | Frequency bands | Comments |
|---|---|---|
| Standard AM broadcast | 540-1600 kHz | |
| FM broadcast | 88-108 MHz | |
| Television | 54-72 MHz | VHF (very high frequencies) |
| 76-88 MHz | TV | |
| 174-216 MHz | UHF (ultra high frequencies) | |
| 420-890 MHz | TV | |
| Cellular Mobile Radio | 896-901 MHz | Mobile to base station |
| 840-935 MHz | Base station to mobile | |
| Satellite Communication | 5.925-6.425 GHz | Uplink |
| 3.7-4.2 GHz | Downlink |
Table 15.2Some Important Wireless Communication Frequency Bands
| Service | Frequency bands | Comments |
|---|---|---|
| Standard AM broadcast | 540-1600 kHz | |
| FM broadcast | 88-108 MHz | |
| Television | 54-72 MHz | VHF (very high frequencies) |
| 76-88 MHz | TV | |
| 174-216 MHz | UHF (ultra high frequencies) | |
| 420-890 MHz | TV | |
| Cellular Mobile Radio | 896-901 MHz | Mobile to base station |
| 840-935 MHz | Base station to mobile |