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 was developed by the company Ibiquity and, with the aid of a decoder, 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 1: Location Of IBOC Decoder In CIC

Courtesy of BMW OF NORTH AMERICA, INC.

IBOC DECODER EXPLANATION CHART

Index	Explanation
1	FM/AM antenna connection
2	FM-TMC module
4	FM/AM double tuner module
5	IBOC decoder

Fig 2: IBOC Station List Menu

Courtesy of BMW OF NORTH AMERICA, INC.

There are two types of broadcast services:

MPS = Main Program Service
SPS = Secondary Program Service

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 3: Sub-Menu Of IBOC Main Station

Courtesy of BMW OF NORTH AMERICA, INC.

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.