When mobile phones first entered cars, their uses were limited to telephony via a hands-free setup. Now, these devices are increasingly being used to access the Internet on the road to contact local services or augment satellite-based navigation. A significant and increasingly important function is navigation responding to the momentary traffic situation. It determines how many mobile phone subscribers are logged into a cell and at what speed they are moving. The more such subscribers present in a cell and the slower they are moving, the denser the traffic or else a traffic jam has built up.
Another combined option for satellite-based navigation and mobile phones is offered by emergency call systems--such as eCall--that are used in the event of an accident or breakdown. This intelligent emergency call system determines the position of the vehicle via satellite and sets up a data and voice link to an emergency call center via the mobile communications network. Vehicle fleet management and the German toll system, for example, also operate with satellite-based navigation and mobile communications technology. The frequency ranges they use depend on the regions in which they operate.
An extensive range of AEC-Q200-qualified EPCOS SAW filters (single and diplexer) is also available in package sizes of 3.0 × 3.0 mm² down to 1.4 × 1.1 mm² with various center frequencies, insertion losses and useful bandwidths for the typical frequency bands. A selection from the current product range is shown in Table 2.
Table 2: AEC-Q200-qualified EPCOS SAW filters for mobile-communications-based applications. For full resolution click here.
All the listed RX filters and 2in1 components have unbalanced inputs of 50 Ω and balanced outputs of 150 Ω. All listed TX and RX diversity filters have unbalanced inputs and outputs of 50 Ω.
Join our online Radio Show on Friday 11th July starting at 2:00pm Eastern, when EETimes editor of all things fun and interesting, Max Maxfield, and embedded systems expert, Jack Ganssle, will debate as to just what is, and is not, and embedded system.