Audio System Controller (ASK)
Audio System Controller
In the past, each system used its own output media (e.g. gong, dual cone speakers etc.) which generated a number of different sounds in the car. It was often not possible to achieve coordination between these sounds or at best, it could be done only in particular cases.
This created situations where acoustic information for other sources had to be suppressed, otherwise the driver would have been faced with a confusing mix of acoustic signals.
On the E65/E66, a control unit has been developed to control, coordinate and generate acoustic signals according to priority: the Audio System Controller,(ASK).
The Audio System Controller (ASK) has three main functions.
- Network master
- Audio master
- Connection master
Network Master
The ASK performs the role of network master for the MOST bus. The functions of the network master are the following:
- Wake-up, initialization, power-down
The network master wakes up the bus and has the task of achieving an orderly initialization of the network. The ASK can operate with KLR off. To turn it on, push in the volume/ON/OFF knob. Adjustments and control is carried out by using the Controller and Control Display.
Another task of the network master is to control the power-down process. Each powerdown is initiated and started by the ASK.
- Configuration control
The network master detects the exact system configuration each time that the network is started and compares it to the stored coded configuration.
- Control of the network operation
The network master controls the MOST transceiver of the slave equipment for correct operation. The equipment which is not operating properly will be released by a reset or switched to low power mode so that they do not affect bus communication.
- Fault code memory
The network master includes the fault code memory of the MOST network. It stores all the faults occurring during the network operation as well as deviations from the nominal configuration.
Audio Master
As audio master, the ASK has the task to collect and process all the audio signals of the vehicle and to distribute them to their destinations.
The ASK controls all the acoustic requests from the Control Display. The changes in the level of a signal is not sudden, but smooth, e.g. during suppression, insertion and fading out or temporary suppression of the signal at the destination: Because of this, a high-quality acoustic sound is obtained.
The ASK also assumes the generation and preparation of different acoustic signals, e.g. PDC signals and warnings. In the event of a request for a warning or caution signal from a control unit, the ASK provides a clean acoustic change of the signals.
- Audio data
All audio data from any control unit are converted by the ASK into digital audio AF format at a sampling rate of 44.1 KHz.
- Categorization of audio sources
All possible audio sources are divided into different groups according to priority. Warning signals have priority over any other audio source. Mixing of lower priority audio signals (e.g. navigation, radio) is possible.
- Generation of acoustic gongs
These are acoustic alarm signals which help the driver perceive sounds according to a system. The different sounds, requested by the different control units,(e.g. gongs, PDC, etc..), must be generated only in association with a visual indication. These come from the instrument cluster and the Control Display.
The following sounds can be generated in the ASK.
- Beeping for the PDC.
- Various Check Control and warning gongs.
Output of Audio Signals
The output of audio signals occurs under the following conditions:
- Two gong signals are never output simultaneously.
- It is possible to generate a maximum of 3 signals at the same time.
- If the input includes a fourth signal, the signal at the lowest priority is muted.
- When issuing the 3 higher priority signals, the entertainment source is suppressed (radio). If the entertainment source is a CD, it is stopped and switched off. When the CD is reactivated, it restarts from the point where it was stopped.
Examples of audio output:
Radio:
The radio plays in the background, the PDC is active and a navigation message is output. If a gong request comes, the radio is muted and the gong is generated.
Telephone:
When the hands-free function is activated the loudspeakers are muted. Gongs are mixed as required according to their priority. The Speech Processing System is not active when the hands-free function is used.
Speech Processing System:
When the voice processing system is activated, a general mute suppresses the loudspeakers. Gongs are mixed as required according to their priority. The hands-free operation and the navigation messages interrupt the Speech Processing System.
Connection Master
As connection master, the ASK must provide channels to the equipment connected to the bus and distribute the audio signals on the outputs (loudspeakers).
The connection master also controls the basic Hi-Fi or the LOGIC 7 Hi-Fi amplifiers.