Harman Becker Automotive Systems Gmbh

Harman Becker Automotive Systems (becker Division) Gmbh

Stefan Gierl

Christoph Benz

Joachim Wietzke

Andreas Körner

Hans-Juergen Nitzpon

Erich A Geiger

Dieter Jurzitza

Andreas Koerner

Karl-Anton Becker

Dieter Jurzizta

A system for decoding a stereo multiplex signal, including one or more devices operable to convert the stereo multiplex signal into a sum signal (L+R) and a difference signal (L&#x2212;R). The sum signal and the difference signal may be derived from a left stereo signal (L) and right stereo signal (R). The system may also be operable to determine a first transfer function H(f) and a second transfer function (H(f)) from the sum signal (L+R) and the difference signal (L&#x2212;R). Further, the system may be operable to filter the sum signal (L+R) according to the first transfer function to provide the left stereo signal (L), and filter the sum signal (L+R) according to the second transfer function to provide the right stereo signal (R).

Stereo decoding system

A processing front-end for FM radio signals includes a receiver, a filter, and a mixer. The receiver obtains an FM radio signal including data content centered at a data frequency and programming content. The filter is coupled to the receiver and removes the programming content from the FM radio signal. The mixer accepts the filtered FM radio signal and shifts the center frequency of the data content to a lower frequency than the first frequency. The lower frequency is selected according to a sampling rate available in an analog-to-digital converter present in a subsequent processing stage, typically a low cost digital signal processor.

FM radio receiver processing system

In order to suppress as much noise as possible in a hands-free device in a motor vehicle, for example, two microphones (M, M) are spaced a certain distance apart, the output signals (MS, MS) of which are added in an adder (AD) and subtracted in a subtracter (SU). The sum signal (S) of the adder (AD) undergoes a Fourier transform in a first Fourier transformer (F), and the difference signal (D) of the subtracter (SU) undergoes a Fourier transform in a second Fourier transformer (F). From the two Fourier transforms R(f) and D(f), a speech pause detector (P) detects speech pauses, during which a third arithmetic unit (R) calculates the transfer function Hof an adaptive transformation filter (TF). The transfer function of a spectral subtraction filter (SF), at the input of which the Fourier transform R(f) of the sum signal (S) is applied, is generated from the spectral power density Sof the sum signal (S) and from the interference power density Sgenerated by the adaptive transformation filter (TF). The output of the spectral subtraction filter (SF) is connected to the input of an inverse Fourier transformer (IF), at the output of which an audio signal (A) can be picked up in the time domain which is essentially free of ambient noise.

System for suppressing ambient noise in a hands-free device

The sound reproduction of a multichannel sound reproduction system with a plurality of speakers which is connected to the output of an FM stereo receiver is controlled by a control signal derived from the reception quality. Preferably, the control signal from the FM stereo receiver for controlling the stereo and mono components is also employed to control the multichannel sound reproduction system. For example, stereo, pseudo-stereo or mono reproduction are provided in the multichannel sound reproduction system in response to the stereo component within the output signal.

Apparatus for multichannel sound reproduction system

A method and apparatus for operating a radio reception system, which comprises a plurality of receivers assigned to a common output device, in which one of the receivers is designated as audio receiver and is tuned to a frequency of a radio transmitter, and outputs a signal received from the transmitter to the output device. At least one second receiver is designated as search receiver, and continuously searches its own reception frequency band for a frequency of the same transmitter. The system changes to a frequency of this transmitter, which was found by the search receiver, if the quality of the signal received by the audio receiver falls below a certain limit.

Radio reception system with automatic tuning

This invention provides a signal synchronizer that is capable of minimizing the effects of multi-path reception. The signal synchronizer provides signal samples from a first signal source and a second signal source for generating an output signal. The signal synchronizer includes a memory for storing signal samples obtained from a first signal source and for storing signal samples obtained from a second signal source. Circuitry in the synchronizer determines a signal transit time difference between the first signal source and the second signal source. A readout controller then determines a memory offset from the signal transit time difference. The memory offset specifies a location in the memory from which to begin reading the signal samples obtained from the second signal source.

Multipath compensation for signal receivers

Method for supressing surrounding noise in a hands-free device and hands-free device

A motor vehicle entertainment system includes a radio receiver and a control unit. The control unit receives a first status signal indicative of whether or not a motor vehicle door has been unlocked and initiates the application of power to the radio receiver upon the first status signal indicating that the door has been unlocked. Upon the application of power to the radio receiver, the radio receiver scans through a selected frequency spectrum to identify valid frequencies and their associated broadcast identifying information and stores a list of the valid frequencies and their associated broadcast identifying information in a memory device associated with the radio receiver. The radio receiver acquires and records information on a plurality of transmitters initially in a standby mode before it switches over to an operating mode. The radio receiver has a device for receiving an ON command from the user and switches from the standby mode to the operating mode when the ON command is received. The radio receiver may begin to operate before the ON command is input by the user, and independently of this input. If the radio receiver begins to operate in sufficient time before input of the ON command, then collection of transmitter information by the radio receiver may already be complete before the user inputs the ON command, which is typically indicative of the desire of the user to listen to an audio signal.

Radio signal receiver

An apparatus determines an optimal antenna and frequency combination by selecting the optimal antenna from among a plurality, N, of antennas associated with a receiver and also selects the optimal frequency from among a plurality, M, of alternative receiving frequencies transmitted from a transmitter. This is achieved by determining all N&#xd7;M possible antenna/frequency combinations, by determining the received signal quality at each combination, by comparing the N&#xd7;M received signal qualities, and by selecting the one antenna/frequency combination having the optimal received signal quality.

Antenna and frequency diversity receiving apparatus

A system for decoding data, such as travel and traffic information, configured in data blocks embedded in an electromagnetic signal, such as a broadcasted radio signal, has been developed. The system includes a method and receiver for decoding the data with a background tuner in a manner that does not impair the ability of the background tuner to demodulate other signals. While a main tuner is tuned to demodulate a first electromagnetic signal to produce a data stream, the background tuner is switched to decode the data blocks only when the data blocks are expected to be received. In the remaining time, the background tuner is free to demodulate other signals to support a diversity or other function. If a data block is not received, or not received when expected, the background tuner returns to demodulating one or more other frequencies after a predetermined time interval has elapsed.

Receiver system for decoding data embedded in an electromagnetic signal

For the purpose of largely suppressing the noise pulses caused in a stereo radio receiver in the reception signal, particularly by the ignition system of a motor vehicle, a digital field strength signal representing the analog field strength signal is produced for example by digitizing the analog field strength signal. The scanning values of the digital audio signal, for example of the (L+R) signal, are produced by interpolation for at least as long as the digital field strength signal is outside a presettable tolerance range.

Stereo radio receiver with noise suppression

A phase-locked loop locks relatively quickly to a pilot tone of the stereo-multiplex signal when a new transmitter is tuned in. The stereo-multiplex signal may be multiplied in a multiplier by the quadrature component of the pilot tone generated by a digital oscillator. The result is a control signal that is provided to a low-pass filter, and the low-pass filtered control signal is provided as a control signal to an oscillator which may include a table of length N and a counter for addressing the table entries. The zero phase angle &#x3c6;may be set by a counter offset nby incrementing or decrementing the counter. A table may be utilized having a virtual length N+ which is larger than the length N of the real table. To access the real table, however, the corresponding MSBs of the actual count n(k) are used which match the address space of the real table of length N.

Phase-locked loop for synchronization with a subcarrier contained in an intelligence signal

Apparatus and method for multichannel sound reproduction system

To demodulate the RDS signal, the stereo-multiplex signal is multiplied in a first branch by the in-phase component of an oscillator filtered by a low-pass filter while decimated in its sampling rate and filtered by a high-pass filter while in a second branch it is multiplied by the quadrature component of the oscillator filtered by a low-pass filter decimated in its sampling rate, and filtered by a high-pass filter. An error signal to control the oscillator is calculated from the high-pass-filtered signals and the RDS bit clock. A clock generator generating the RDS bit clock is controlled by the first high-pass-filtered signal and by the oscillator. An RDS decoder, to whose input the first high-pass-filtered signal is applied. and an arithmetic unit which calculates the error signal from the high-pass-filtered signals and from the PDS bit clock are both clocked by the clock generator. The RDS data are retrievable from the output of the RDS decoder.

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Karlsruhe, Germany

Stefan Gierl