Abstract:
In a circuit arrangement for deriving a signal dependent on the change direction of the incoming signal level in a radio receiver, controllable by a microcomputer, a comparator is provided outside the microcomputer to which a signal representing the respective signal strength and a signal generated by the microcomputer representing the signal strength at an earlier point in time can be supplied. An output signal from the comparator can be supplied to the microcomputer.
Abstract:
The method for obtaining the quality signal includes multiplying a digital multiplex signal (MPX) by respective reference carrier signals mutually phase shifted by 90.degree. to each other, but otherwise equal, to form a pair of mixed signals (Imr1,Imr2); multiplying the mixed signals (Imr1, Imr2) by respective correction signals (G38c,G38s) to form a pair of corrected mixed signal (Ims1,Ims2); separately multiplying the digital multiplex signal (MPX) by each of two reference pilot signals mutually shifted in phase by 90.degree. relative to each other to form respective derived signals useful for obtaining said correction signals (G38c,G38s); adding said corrected mixed signals (Ims1,Ims2) to each other; multiplying said mixed signals (Imr1,Imr2) by the respective correction signals (G38s,G38c) to form a pair of product signals; subtracting these product signals from each other to form a subtraction result and low-pass filtering the subtraction result to obtain a low-pass-filtered resultant signal from which the quality signal is derived.
Abstract:
A circuit arrangement for deriving the signal indicating noise in a received stereo multiplex signal, wherein the stereo multiplex signal is present as a digital signal with a first sampling rate that is substantially higher than twice the upper limit of the useful frequency range of the stereo multiplex signal, and the received stereo multiplex signal is passed through a low-pass filter. The low-pass filtered signal and the received stereo multiplex signal are subjected to decimation to a second sampling rate, which is higher than twice the upper limit of the useful frequency range of the stereo multiplex signal. The two stereo multiplex signals with the second sampling rate are subtracted from one another.
Abstract:
In a radio receiver with digital signal processing, a stereo multiplex signal received and the useful signals derived therefrom are processed in digital form at a first sampling rate. The subsidiary signals derived from the stereo multiplex signal are at least partly processed at a second sampling rate that is smaller than the first sampling rate. The sampling rate of the processed subsidiary signals are reduced to the first sampling rate with the processed subsidiary signals, acting as control signals with the first sampling rate, affecting the stereo multiplex signal and the useful signals.
Abstract:
The circuit arrangement includes a first low-pass filter (2) for filtering an input signal (H3) proportional to the strength of a received radio signal; a second low-pass filter (3) for filtering the input signal (H3); a first weighting circuit (7) for weighting the first low-pass filter output signal with first coefficients to form a first weighted output signal; a circuit device for forming a masking signal for reducing stereo channel isolation from the first weighted output signal; a second weighting circuit (5) for forming a second weighted output signal weighted with second coefficients from the first low-pass filter output signal or the second low-pass filter output signal according to a switching signal (DD2) indicative of interference in the audio signals; a switch device (4) for selecting the first low-pass filter output signal for weighting in the second weighting circuit means (5) when no interference is indicated by the switching signal (DD2) and the second low-pass filter output signal for weighting in the second weighting circuit means (5) when interference is indicated by the switching signal (DD2); and a circuit device for forming a masking signal for damping the audio signal from the second weighted output signal.
Abstract:
A radio receiver is provided having digital signal processing, a first and a second auxiliary signal derived from a received stereo multiplex signal, the first auxiliary signal being dependent upon the existence of signal components, whose frequency lies above the fundamental frequency range of the stereo multiplex signal, and the second auxiliary signal being dependent upon the symmetry of the sidebands of the stereo subcarrier. The first and the second auxiliary signal are combined to form an interference signal indicating the existence of interference. At least one control signal is derived from the interference signal to influence the audio signals acquired by decoding the stereo multiplex signal.
Abstract:
In a circuit for digital processing of audio signals in a radio receiver, preferably in a car radio, the audio signals pass through a digital filter designed as a tone control, whose frequency response can be controlled with supplied coefficients, and a volume control, whose transmission factor can be controlled with supplied control signals. If the high and/or low frequencies are raised, the transmission factor of the filter at medium frequencies can be correspondingly lowered. Volume control compensates for the reduction. The volume control may contain a digital and an analog portion.
Abstract:
A drive for storage disc which permits a convenient means of loading and unloading the storage disc. The drive includes a loading device for transport of a storage disc into the drive, the loading device including a carrier for accommodating the storage disc. In a loading position, the carrier remains generally in the drive and, in the direction of an insertion opening of the drive, includes an opening for insertion of the storage disc.
Abstract:
A method is proposed that is used for activating the functions of an electrical device, preferably a car radio. A test routine stored in a storage area allocated to the device is executed by a control unit of the electrical device. The control unit activates at least one function of the electrical device on the basis of control commands predefined in the test routine. Information about the function just activated is reproduced on a reproducing device of the electrical device.
Abstract:
In a circuit for decoding a multiplex signal in a stereo receiver, where the multiplex signal contains a composite signal (L+R) in the base band, a subcarrier modulated with a difference signal (L-R), and a pilot signal with half the frequency of the subcarrier, the multiplex signal in digital form is multiplied (2, 3) by a reference carrier generated with a sampling clock signal (14) produced in the radio receiver, where the reference carrier is present in two phase positions shifted 90.degree. with respect to each other. The mix or product signals resulting from this multiplication are multiplied (4, 5) by one correction signal each, thus forming corrected mix signals. The corrected mix signals are added (6) and supplied to a matrix circuit (8, 9), together with the composite signal, to create respective stereo audio channel signals (L, R).