Radio, Stereo, and Compact Disc: Description and Operation
Audio System
COMPONENT LOCATION
OVERVIEW
The audio system contains the following functions:
^ CD player
^ AM/FM tuner
^ DAB/SDARS radio systems (where available)
The audio system is available in 2 versions, Standard and Premium.
The Standard audio system uses an internal amplifier which directly drives the system speakers and contains a single disc CD player. The Standard audio system is controlled purely from the head unit and the remote steering wheel controls. The head unit is connected to the vehicle on the medium speed CAN bus. This allows the unit to be interrogated for diagnostic purposes.
The Premium audio system comprises the following components:
^ Integrated Audio Module (IAM)
^ Infotainment Control Module (ICM)
^ Separate audio amplifier
^ Rear seat audio control modules with head phone sockets
^ Surround sound speaker system
Control of the Premium audio system is via the ICM located in the center of the instrument panel. Control signals from the ICM are sent to the rest of the audio system on the Media Orientated System Transport (MOST) ring. The ICM is the timing master for the MOST ring and also hosts a gateway function between the medium speed CAN bus and the MOST ring. Audio signals are sent on the MOST ring from the Integrated Audio Module to the amplifier.
LOW LINE AUDIO SYSTEM
The low line Head Unit (HU) contains the following functionality:
^ AM/FM Radio tuner
^ Single disc CD (compact disc) player
^ Amplifier
The HU communicates with other vehicle systems on the CAN (controller area network) bus.
The HU is contains an internal amplifier which directly drives the vehicle speakers.
The HU incorporates a power management function. Should the vehicle battery level drop below a predetermined level the unit will limit its functionality. The HU receives CAN (controller area network) signals which help it determine the wake up/shut down process.
Transit Mode
Transit mode is used to reduce the vehicle battery current drain whilst the vehicle is being stored or transported. Transit mode is entered/exited via a CAN signal from the Land Rover recommended diagnostic tool. In transit mode the following circuits will be disabled:
^ Aux and phone call
^ Clock
^ Antenna power
^ LED (light emitting diode) illumination.
In transit mode the CAN (controller area network) port and the ON/OFF switch are the only circuits that are left active.
The CAN port is left open to allow the EXIT from transit mode signal to be received. The ON/OF switch is left active to allow feedback to the driver via the HU LCD (liquid crystal display), that the unit is in transit mode should the driver attempt to power up the HU. This will only occur when the vehicle engine is running and the battery is above 12.3 Volts.
HIGH LINE AUDIO SYSTEM
The High Line Audio system is based around an Integrated Audio Module (IAM) which communicates on the Media Orientated System Transport (MOST). The ICM module communicates on medium speed CAN & MOST buses.
The IAM contains the following functionality:
^ Radio tuner
^ CD player (Single CD or Six disc in dash changer)
^ Auxiliary input (for any device featuring a 3.5mm jack plug output).
The ICM is woken up by CAN bus activity. The IAM is woken up by MOST ring.
The ICM is the Bus Master for the MOST system and contains the timing master for the MOST system.
TUNER
The IAM incorporates a AM/FM tuner which allows for 30 FM pre-sets (FM1 FM2 FM a) and 20 AM (10 AM & 10 AM a, for Europe the 10 strongest LW & MW will be stored in frequency order). Pre-set stations are stored in the IAM & ICM memory. The radio tuner also incorporates the following radio functions:
^ Auto tune
^ Traffic announcements (TA) - Europe only
^ Radio Data System (RDS) EON function (Radio Broadcast Data System RBDS in NAS markets)
^ Seek station
^ Tune up/down
^ Scan
^ PTY
CD PLAYER
The IAM CD player is a 6 disc multi changer located in the center of the instrument panel. The CD multi changer is capable of playing commercial CDs, CDRs, CDRWs and MP3 discs.
Random Play
The random play feature works in two different manners:
^ Random play of tracks on a CD
^ Random play of all tracks on any CD in the autochanger
The single disc random feature plays all the tracks on the selected CD in a random order. All the tracks on that disc will be played before a new random sequence is played. If a new CD is selected while in random mode, the random mode will be cancelled and play will commence from the first track.
In multi disc mode the I AM uses the current track is the fist random track and will then play a further 2 tracks (if available) from this CD. The IAM will then randomly select another CD, and play 3 random tracks. This sequence continues until all tracks from all CD's are played back.
MP3 Function
The CD player has the capability to play MP3 files. The MP3 discs follow a format of folders and files within the folder. It is also possible to place all the files in the root directory on the CD.
The random and repeat features follow the normal CD random and repeat feature functions.
Automatic Volume Control (AVC)
AVC controls the audio volume in relation to vehicle speed. As vehicle speed increases the audio level is adjusted to compensate for extra road and vehicle noise. There are 4 settings for AVC:
^ Off
^ Low
^ Medium
^ High
The default setting is medium.
Changing the AVC level is accessed by a long press of the TONE button and selection of the AVC using the rotary encoder to change the level.
The vehicle speed signal is used to enable the ICM to calculate the volume adjustment required. The vehicle speed signal is received over the CAN. The signal is an average of the four wheel speed sensor signals. Should an invalid speed signal be received the AVC will not alter the output volume.
AVC is controlled by the audio amplifier.
CD Error Messages
When an CD error occurs, the IAM will alert the user by showing a display related to the error. This will be displayed while the CD audio mode is selected until the error is corrected. The CD related error does not affect other areas of the IAM. The user is able to select a different audio source.
AUXILIARY SOCKET
The auxiliary connector is located at the rear of the center console. AUX (Auxiliary Input) mode allows extra equipment to be connected to the vehicle's audio system. Items such as a personal stereo, MP3 player, hand-held navigation unit etc., can be plugged in to the vehicle's audio system.
To listen to an auxiliary input source the portable device must be connected via the 3.5 mm stereo jack socket. If the device has a line out socket it is preferable that this is used for connection. Press and hold the AUX button on premium audio units. On standard audio units, press and release the AUX button.
REAR SEAT HEADPHONE MODULES
The rear seat headphone modules are located on the rear of the center console. The rear seat headphone modules allow the rear seat passenger to listen to audio via standard headphones. The modules allow the rear seat passengers to control which audio source they want to listen to and the volume. The rear headphone modules do not override the control of the audio head unit.
STEERING WHEEL CONTROLS
The steering wheel mounted audio control switches are located on the RH side of the steering wheel. The switches are a resistive ladder type which return a different voltage to the ICM in response to different switches being pressed.
SDARS
The SDARS systems operate in the S-Band frequency range (2.3 GHz) and, as a result of the use of satellite transmission have the ability to provide CD quality audio broadcasts over very large areas (typically continents). SDARS service providers transmit a signal from their up-link facility (which is the original point of transmission of data, voice or other information through an antenna system) to a satellite where the signal is then down linked to both the terrestrial repeater network and the individual SDARS car radios. The radio switches between the satellite signal and the repeater signal depending on the strength of the signal at any given time.
Land Rover will be using the Sirius Satellite Radio service provider in the USA.
The SDARS systems comprise:
^ Satellites
^ Ground repeaters
^ Up-link ground stations
^ Radio receiver systems
The SDARS system uses three satellites on an inclined elliptical orbit. This ensures that each satellite spends approximately 16 hours a day over the continent of the USA, with at least one satellite over the country at any one time.
The satellites beam their signals down to the ground where the signal is picked up by receivers or is transmitted to repeater stations to cover built up areas where the signal is obscured.
SDARS is a subscription based service which requires the user to contact Sirius to obtain a subscription. In order to obtain a subscription the SDARS unit ID number will need to be retrieved from the unit. This is achieved as follows:
^ Press the MENU button and then rotate the menu control to scroll to advanced settings.
^ Rotate the menu control to scroll to SIRIUS ID and press the menu control to select it.
^ The Sirius ID is shown on the display screen.
If no subscription has been taken the ICM will display the Sirius telephone number. To subscribe to Sirius use the displayed phone this number. The user will need payment details, the Sirius ID number and details of the required package.
The SDARS function is accessed by pressing the FM button and then pressing again to toggle through the SAT1 and SAT2 sources. SAT1 and SAT2 operate in the same manner as FM1 and FM2.
The SDARS module is located in the rear LH side of the luggage compartment. The SDARS module is connected to the rest of the audio system on the MOST ring. This allows control signals and received audio to be routed around the system to the relevant module. The SDARS antenna is located in the roof mounted pod and is hardwired to the SDARS module.
CLOCK
The ICM contains the master clock functionality. Other vehicle infotainment modules that require clock functionality use the time supplied from the ICM.
The clock is available to any control module that is connected to an interconnecting bus i.e. either of the CAN busses or the MOST ring.
The clock display configurable to show in AM / PM or 24 hour format. Midnight is shown as 12:00AM or 0:00 respectively. The default condition, if not specified, after power on or delivery, should default to 12:00PM or 00:00. Depending upon the market set the clock will default to either 12 or 24 hour format.
The time is adjusted from the ICM. Under conditions when any bus could be asleep or shut down, the HMI does not allow clock adjustments.
AMPLIFIERS
The audio system has three amplification options dependant on the audio system specified:
^ Internal amplifier
^ Harman kardon
^ Harman kardon LOGIC 7
The amplifier is located under the RH front seat and is connected to the audio system via the MOST bus. Speaker connections are hardwired.
CONTROL DIAGRAM
