Radio, Stereo, and Compact Disc: Description and Operation
Audio System
Integrated Head Unit (IHU) Audio System Component Location
Integrated Head Unit (IHU) Audio Control Diagram
Integrated Head Unit
NOTE: The base level audio system IHU comprises a single disc CD (compact disc) player and an integral amplifier, all other functions of the unit are comparable with the 6 disc unit.
The audio system is based around an Integrated Head Unit (IHU) which communicates on the Media Orientated System Transport (MOST) ring and the medium speed CAN (controller area network) bus.
The IHU contains the following functionality:
^ Radio tuner.
^ CD (compact disc) player (Six disc in dash changer).
^ Integrated telephone control.
^ Auxiliary input (for any device featuring a 3.5mm jack plug output).
The IHU (Integrated Head Unit) unit also integrates with the navigation system, this requires the addition of a navigation computer, touch screen display and GPS (global positioning system) antenna.
The IHU is woken up by CAN (controller area network) bus activity and is not woken up from the ignition aux position.
The IHU is the Bus Master for the MOST system and contains the timing master for the MOST system.
Connector C1354 Pinout Table For High Line Audio
Connector C2115 Pinout Table
Tuner
The IHU incorporates a AM (amplitude modulation) /FM (frequency modulation) tuner which allows for 18 FM (frequency modulation) pre-sets and 18 AM (amplitude modulation) (9 MW and 9 LW) pre-set stations to be stored in the IHU memory. The radio tuner also incorporates the following radio functions:
^ Auto tune
^ Traffic announcements (TA)
^ RDS (radio data system) EON function
^ Seek station
^ Tune up/down
^ Scan
^ PTY
CD (compact disc) Player
The CD (compact disc) player is a 6 disc in dash mounted device. The CD (compact disc) multi changer is capable of playing commercial CD (compact disc) s, CD (compact disc) Rs, CD (compact disc) RWs and MP3 discs.
Random Play
The Random feature only works on the CD (compact disc), which has been selected. The Random feature plays all the tracks on the selected CD (compact disc) in a random order. All the tracks on that disc will be played before a new random sequence is played. If a new CD (compact disc) is selected while in random mode, the random mode will be cancelled and play will commence from track 1.
Repeat
The Repeat feature allows the current track to be repeated in an endless loop, when selected by the user.
MP3
The CD (compact disc) 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 (compact disc). The random and repeat features follow the normal CD (compact disc) random and repeat feature functions.
Scan
Scan allows the user to play the first 10 seconds of each track on the CD (compact disc) in the unit.
Automatic Volume Control - AVC
The AVC feature is designed to adjust output volume to compensate for the rising level noise of the vehicle as the vehicle travels faster.
There are 10 settings for AVC, where 0 = off, 1 is the lowest setting (minimum volume change with speed and 9 the maximum).
The vehicle speed signal is used to enable the IHU to calculate the volume adjustment required. The vehicle speed signal is received over the CAN (controller area network). The signal is an average of the four wheel speed sensor signals.
Control of the AVC is carried out by the audio amplifier.
Should an invalid speed signal be received the AVC will not alter the output volume.
Clock
The IHU contains the master clock functionality. The IHU contains and displays the clock in one unit. Other vehicle modules that require clock functionality use the time supplied from the IHU.
The clock is available to any control module that is connected to an interconnecting bus i.e. either of the CAN (controller area network) 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 1:00PM or 13:00. Depending upon the market set the clock will default to either 12 or 24 hour format.
The time is adjusted from the IHU. Under conditions when any bus could be asleep or shut down, the HMI does not allow clock adjustments.
Amplifiers
Harman Kardon High Line/Logic 7 Amplifier
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 (right-hand) front seat and is connected to the audio system via the MOST bus. Speaker connections are hardwired.
Speaker Connector C0491 for Harman Kardon Amplifier
Speaker Connector C0491 for Harman Kardon Logic 7 Amplifier
Speaker Connector C0492 for Harman Kardon Amplifier
Speaker Connector C0493 for Harman Kardon Amplifier
Speaker Connector C0492 for Harman Kardon Logic 7 Amplifier
Speaker Connector C0493 for Harman Kardon Logic 7 Amplifier
Steering Wheel Control Switches
The IHU can be remotely controlled via steering wheel mounted controls. The audio steering wheel controls are mounted to the RH (right-hand) side of the steering wheel with the voice recognition system control (push to talk switch) located on the LH (left-hand) side of the steering wheel behind the speed control switches.
The Steering wheel control switches allow the driver to:
^ Change audio system mode
^ Adjust audio volume
^ Change CD (compact disc) tracks
^ Activate the voice recognition system
^ Change radio pre-sets
^ Tune up/down
^ Answer and end a phone call (where a phone is fitted)
^ Use the voice recognition system.
The switches operate on a resistive ladder principle. A voltage is supplied to the switches and dependant upon which button is pressed a reduced voltage is returned to the head unit.
Satellite Digital Audio Radio Service (SDARS NAS Only)
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 (compact disc) 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 Sirius SDARS systems comprise:
^ Satellites Ground repeaters
^ Up-link ground stations
^ Radio receiver systems
The Sirius 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.
Traffic Message Channel (TMC)
The TMC system is a European only system whereby traffic information is received by the TMC tuner and used by the navigation computer to recalculate the route being used to avoid the traffic disruption. This system information is broadcast on the RDS (radio data system) data carriers.
The information is used by the navigation system to avoid traffic disruptions on a planned route