Functional description

The TV function is realized in the video module (VM). The TV picture is displayed on the Central Information Display (CID) and, depending on the vehicle equipment, on the rear monitor.

The video module modulates the high-frequency aerial signal (HF signal) that is fed over two or three aerial inputs, to a digital baseband signal.

During the process, both of the inputs are used for the reception of the actual dialled-in programs in the video module with the two aerial inputs. This mechanism, called MRC (maximum ratio combining), combines both reception paths. With it, an optimal mobile receiving power is achieved. Station searches are not performed in the background while driving (list of stations update). The video module performs the station searches when in standstill (driving speed below 5 km/h) during suitable reception conditions.

During suitable reception conditions, the video module with three aerial inputs uses the third aerial input for the station search in the background and thereby continuously updates the list of stations. In the process, the allocation between the aerial input and the reception paths for the station search (MRC function) of the video module is continuously reconfigured and is not firmly assigned.

All video modules try to maintain the currently selected station when changing to another service area (called: DAB/FM changeover). For the video module with two aerial inputs, the DAB/FM changeover can lead to a momentary break in reception due to the system architecture. For a video module with three aerial inputs, the DAB/FM changeover is virtually unnoticeable for the user.

For the Japanese version, the service 1-Seg (1 segment mode) is also supported in the ISDB-T.

Fig 1: Identifying Video Module Components

Courtesy of BMW OF NORTH AMERICA, INC.

The following graphic shows the slot for the decoding card on the reverse side of video module with the video module in the Japan version as an example.

Fig 2: Identifying Video Module

Courtesy of BMW OF NORTH AMERICA, INC.