BMW 7 Series: IBOC System/HD Radio

The IBOC (In-Band- On-Channel) system is offered as the digital radio. With the introduction of the CIC, the control unit of the IBOC system has been integrated in the head unit as the IBOC decoder.

The IBOC system enables the reception of HD (High Definition) radio through the FM/AM double tuner.

This system simultaneously broadcasts an analog and digital signal.

A special oscilloscope (spectrum analyzer) would show the digital components at both sides of the analog wave of the FM frequency (step shape).

The IBOC system receives the signals with the aid of the FM double tuner module.

These signals are then routed to the IBOC decoder which adds the digital data stream to the audible music signals.

Fig. 99: Identifying IBOC Decoder

INDEX REFERENCE CHART

1. FM/AM antenna connection
2. FM-RTTI module
3. FM/AM double tuner module
4. IBOC decoder

There are two types of broadcast services:

• MPS = Main Program Service
• SPS = Secondary Program Service

Fig. 100: Display - IBOC Station List Menu

Both services differ to the effect that the signal previously broadcast analog in the MPS is now used in digital form.

The decoder delays digital reception for several seconds until it is synchronous again with the analog signal previously heard.

SPS offers additional radio stations that are only broadcast in digital form. Using the multicast method, it is possible to accommodate up to seven digital stations in the submenu of the SPS main station. Normally, however, a maximum of 3 sub-menu are offered in the SPS.

Fig. 101: Display - IBOC Main Station Sub-Menu

The system automatically switches over to analog FM reception if the digital signal is no longer available.

HD radio is also available in the AM frequency range. In this case, the digital signals are transmitted on directly adjacent frequencies of the analog station. Multicast is not supported on AM. The content of the digitally broadcast station is the same as that of the analog station.

HD radio plays AM radio stations in near-FM quality and FM radio stations in near-CD quality.

CIC Application Board with Processors

The application board accommodates the main processor (Central Processing Unit) and the main memory modules (Random Access Memory) for the CIC. These components are soldered into the board and cannot be replaced.

INDEX REFERENCE CHART

1. CPU - Central processing unit
2. Main memory (RAM) of the CIC

Fig. 102: Identifying CPU And Main Memory (RAM)

Power Board

The power board is located beneath the CIC heat sink and on the left next to the CIC main connector. It contains both the audio output stages for the speakers of the stereo system as well as the power supply unit for the CIC.

The heat sinks and CIC fan cool the system by dissipating the heat from the power supply unit and amplifier.

The unit interfaces with the vehicle's electrical system (power supply, MOST link, etc.) through the main connector.

INDEX REFERENCE CHART

1. Heat sink
2. Power board
3. Main connector of the CIC

Fig. 103: Identifying CIC Main Board, Heat Sink And CIC Main Connector

Amplifiers and Speakers

The speaker systems on the F01/F02 are available in two versions:

• HiFi system (Standard)
• Top-HiFi system. (Option)

The HiFi system is the standard audio equipment for the F01/F02. The HiFi system is equipped with a 8- channel amplifier with digital equalizer. However only 7 of the 8 channels are used in the HiFi system.

The central bass speakers are located under the front seats. They are coupled to the side sills (rocker panels).

That increases the resonance volume necessary for bass reproduction.

The head unit CIC can be combined with any of the two amplifier/speaker systems.

The HiFi and Top-HiFi systems feature separate speakers for the treble and midrange frequencies.

Even though the diameters of the speakers in the HiFi and Top-HiFi systems are the same, there are differences in the power output of the speakers. This is achieved by the use of different materials for the diaphragms, coils and magnets. The designations HiFi and Top-HiFi are used in the table in the next page to distinguish the systems.

The Top-HiFi system achieves double the sound level of the HiFi system.

A digital 10-channel amplifier is used in the Top-HiFi system. However only 9 of the 10 channels are used in the Top-HiFi system.

The Top-HiFi system supports playback of multichannel formats. Multichannel audio formats can be played back with the player in the CIC or with the 6 DVD changer.

Optimum audio reproduction in the vehicle is achieved by way of complex digital signal processing.

The HiFi system has 12 speakers while the Top-HiFi system has 16 speakers each with different auxiliary amplifiers.

The following chart explains the two available sound systems for the F01/F02:

SOUND SYSTEM DESCRIPTION CHART

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