A method for processing an FM stereo signal. The FM stereo signal is digitized and divided into overlapping blocks, which are transformed into the frequency domain. Individual spectral lines of the difference signal are lowered if these have a higher magnitude than the respective spectral lines of the sum signal. The sum and difference signals are then transformed back.

A stereo-phonic frequency modulation receiver includes: a frequency modulation demodulation circuit, receiving a reception signal, and generating a demodulated signal according to the reception signal; a frequency-division demultiplexer, generating a sum signal, a difference signal and a pilot amplitude signal according to the demodulated signal; a dual sound channel separation circuit, generating a left-channel output signal and a right-channel output signal according to the sum signal and a weakened difference signal; and a weakening circuit, weakening the difference signal according to the pilot amplitude signal or a signal-to-noise ratio (SNR) to generate the weakened difference signal.

Disclosed is a frequency amplitude modulation (FAM) transmission apparatus and method by combining a frequency modulation (FM) signal and a digital modulated amplitude modulation (AM) signal. A FAM transmission method includes receiving an FM signal created by modulating an audio signal that includes audio information for mono or stereo broadcasting based on an FM scheme; receiving a digital pulse created by modulating digital data used to provide an additional service for the mono or stereo broadcasting based on an amplitude modulation (AM) affiliated digital modulation scheme; creating an AM signal by by adjusting the digital pulse to have a value greater than 0; and creating a FAM signal by combining the FM signal and the AM signal.

The approach shown provides for an efficient implementation of time response, level response and frequency response alignment between two audio sources such as DAB and FM that may be time offset from each other by as much as 2 seconds, and produces an aurally undetectable transition between the sources. Computational load is significantly reduced over the approaches known in the prior art.

A method for providing a broadcast signal frequency capable of determining an optimal broadcast signal frequency at an accurate location includes collecting vehicle data including location information and information related to a broadcasting function from a plurality of vehicles, determining, based on the vehicle data, a first frequency for receiving a first broadcasting channel with highest reception quality in a first location and a second frequency for receiving the first broadcasting channel with highest reception quality in a second location, and transmitting information on the first frequency and the second frequency to a first vehicle.

A method for providing a broadcast signal frequency capable of determining an optimal broadcast signal frequency at an accurate location includes collecting vehicle data including location information and information related to a broadcasting function from a plurality of vehicles, determining, based on the vehicle data, a first frequency for receiving a first broadcasting channel with highest reception quality in a first location and a second frequency for receiving the first broadcasting channel with highest reception quality in a second location, and transmitting information on the first frequency and the second frequency to a first vehicle.