Selection Of The Individual Antennas (Diversity Function); Selection Of The Various Reception Modes Of The Antenna Diversity Module - BMW F01 Manual

Selected station frequency after bandpass filtering in the tuner module
Index
1
Station frequency after selection by customer
The remaining RF signal is then demodulated in the tuner and output in the form of an
audio signal through the speakers.
The tuner module in the CIC detects that an antenna diversity module is installed and
generates the changeover voltage (Us) and the signal of the intermediate frequency (IF)
necessary for diversity operation.

Selection of the individual antennas (diversity function)

The intermediate frequency is an RF signal (10.7 MHz) and is evaluated by the electronic
circuitry inside the diversity module. The antenna diversity module will switch to the next
FM antenna if the signal quality of the current radio station on the active antenna deterio-
rates to a certain level in terms of quality and field strength.
The changeover takes place in a way that no interruption can be heard.

Selection of the various reception modes of the antenna diversity module

The changeover between AM reception, FM diversity operation and diagnostic mode
occurs in response to the DC voltage Us.
This is performed in the head unit and analyzed in the diversity module with the following
criteria:
• Diversity mode is active when U s = 2.5 V.
• AM mode is active, or the FM1 antenna is selected, when U s = 0 V.
• Diversity mode is active at U s = 5 V.
• The changeover in diagnosis mode to the next antenna takes place by 8 V pulses.
Explanation
81
F01 Audio Systems