Radio/Audio System Description and Operation
Radio/Audio System Description and Operation
The following list shows the radios available for this vehicle:
* U1P - AM/FM, Internal single CD player, and RDS
* UC6 - AM/FM, Internal six CD player, and RDS
* U1A -Navigation Radio, remote six CD player, AM/FM, and RDS
* UZ6 - Audio amplifier with 6 speakers (only available with UC6)
Radio Reception
Radio Signal
The radio signal is sent from a broadcast station and is then received by an antenna. The strength of the signal received depends on the following:
* The power output (wattage) of the broadcasting station
* The location of the vehicle (or receiver) relative to the broadcast tower.
* Obstacles between the tower and the receiver
* Atmospheric conditions
* What band (AM or FM) the station is broadcasting
* Type of antenna and the ground plane
AM Reception
The AM band has a lower frequency range than the FM band. These longer wavelengths:
* Bend around Obstacles
* Follow the curvature of the earth
* May reflect off the ionosphere (skip)
The AM frequencies have longer range due to the ground wave. The ground wave follows the curvature of the earth and is effected by its conductivity. Greater conductivity equates to less signal loss thus transmission over water is better than over land. The AM band has a range of 80-320 km (50-200 miles).
FM Reception
The shorter wavelengths of the higher frequency FM band:
* Reflect off obstacles
* Are absorbed by the ground
* Penetrate the ionosphere
Broadcasts in the FM band are limited to "line of sight" reception which is typically 40 km (25 miles). Even when out of a direct line of sight, the signal may be reflected into areas that would be in a "shadow" otherwise. Factors which affect the line of sight include:
* Height of the broadcast antenna
* Height of the receiving antenna
* Terrain and buildings in the broadcast path
XM Reception
XM satellite radio provides digital radio reception. The XM signal is a broadcast from two satellites and, where necessary, terrestrial repeaters. The high power satellites allow the antenna to receive the XM signal even when foliage and other partial obstructions block the antennas view of the satellites. Terrestrial repeaters are used in dense urban areas. These repeaters will receive the satellite signal and re-broadcast them at much higher power levels in order to ensure reception in areas with densely packed tall buildings.
Audio Amplifier - UZ6
The radio, digital radio receiver, or the CD changer supplies low level audio signals to the audio amplifier in order to boost the signal sent to the speakers.
The radio uses the antenna input signal to create a stereo audio output signal, which is sent at the user-defined volume level to the audio amplifier. The audio amplifier amplifies the signal and sends it to the appropriate speakers. Tone, balance and fade information is sent by the radio to the audio amplifier via a control circuit.
Remote Playback Device - U1A
The radio controls and communicates with the remote playback device via the control circuit.
Remote CD Changer
The remote CD changer allows for multiple compact discs to be played continuously without having to manually change compact discs. Normal size discs may be played using the slots supplied in the magazine. The magazine must first be loaded with discs before it can played. To load CDs, insert the CDs from top to bottom, placing the discs in the magazine label side up. If a disc is loaded label side down, the disc will not play and an error will occur. Care should be used to align and insert the disc into one disc tray only. Repeat this procedure for loading all of the discs in the magazine. Once the discs are loaded into the magazine, open the door on the changer and push the magazine into the changer in the direction of the arrow marked on the magazine and close the door. When the CD magazine is loaded, the changer will begin checking for discs in the magazine. This will continue for up to one and a half minutes, depending on the number of discs loaded. To eject the magazine from the player, slide the CD changer door open. NOTICE: If the CD magazine fails to eject after the door is opened, do not attempt to pry the magazine from the CD changer. Whenever a CD magazine with discs is loaded in the changer, the CD changer symbol will appear on the radio display.
Radio Data System (RDS)
All three audio systems are equipped with technology known as the Radio Data System (RDS). RDS is a system that sends data along with the audio of the FM station you are currently tuned to. RDS is a standard that defines how a FM broadcast station may send digital data along with the audio program. Think of it as a one way wireless modem, allowing the broadcaster to send information about his program to your receiver.
RDS data is carried in what is known as a subcarrier. A subcarrier is a frequency that the FM broadcaster is authorized to use to send data or other audio programs that are not audible in the main audio program. RDS information can be used to display program information and to control the radio.
To receive the RDS signal, all that is needed is an FM receiver with a RDS circuit. A special integrated circuit capable of dealing with the RDS signal is in the RDS circuit and passes it along to the receiver's microprocessor where it is decoded and acted upon.
RDS Basic Information
RDS basic information:
* RDS functions are provided in the FM broadcast band only.
* RDS functions will only work with FM broadcast stations that are broadcasting RDS data.
* Not all FM Broadcast stations broadcast RDS data or offer all of the RDS services.
* RDS functions may not work properly when reception is weak, reception is of poor quality, or RDS is not implemented properly by the FM Broadcaster.
In some cases, a radio station broadcasting incorrect information may cause the RDS features of the radio to appear to work improperly.
Broadcast RDS information can be used in a variety of ways by the receiver and listener, but basically falls into two categories, Display and Control.
Displaying Program Information
RDS displays textual information such as:
* The name of the station
* The type of program
* General information such as artist and song title, call in phone numbers, etc.
Finding an RDS Station
To find an RDS station press the RDS button. The radio will seek to the next RDS station.
XM Satellite Radio
XM is a national satellite radio service that offers up to 100 coast to coast channels including music, news, sports, talk and children's programming. XM provides digital quality audio and text information, including song title and artist name. A service fee is required in order to receive the XM service. For more information, contact XM at www.xmradio.com or call 1-800-852-9696.
Digital Radio Receiver
The radio controls communicate with the digital radio receiver via the class 2 communication circuit. The digital radio receiver sends remote radio audio signals to the radio.
Viewing Messages
Press the DISP or RCL button while in XM mode to view various pieces of information related to the current song or channel. By pressing and releasing the DISP or RCL button, you may view four different categories of information: Artist Name/Feature, Song/Program Title, Channel Category, and other Additional Information that may be broadcast on that channel. Additional Information messages may not always be available. If an Additional Information message is being broadcast on the tuned channel, the INFO icon will appear on the display. Each of the four information types may have multiple pages of text. To reach a category, press and release the DISP or RCL button consecutively until the desired type is displayed. If there are multiple pages of text for the selected information type, the radio will automatically display all the pages for that type at a rate of approximately one page every three seconds before timing out and returning to the default display. You may override this feature by pressing the DISP or RCL button to review all of the pages at your own pace.
