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AssigneesVishay Semiconductor GmbH, ATMEL Germany GmbH, Melexis NV
InventorsMatthias Eichin, Alexander Kurz, Karl-Ulrich Stahl
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Method for interference suppression by means of a quality-adjustable bandpass filter in a receiver circuit for carrier-modulated received signals (SIN), in which the bandpass filtered received signal (Bout) is demodulated, and a switching process is triggered with the demodulated received signal (Dout). Known receiver circuits, however, have the disadvantage, due to small dimensions of the circuit surface area, that interferences, for example in the form of oscillator oscillations due to capacitive couplings, are caused by switching processes in the output portion of the receiver, especially by driving transistors. These interferences cannot be eliminated by an amplifier regulation provided in the circuit. According to the invention, such internal or self-induced interferences or disturbances are eliminated in that a quality reduction of the bandpass filter is correlated with the switching process that causes the interference. The method according to the invention is especially suitable for the construction of circuits for infrared receivers, which can thereby be manufactured in a small size, without external components, and thus economically.
Method for interference suppression by means of a quality-adjustable bandpass filter (23) in a receiver circuit for carrier-modulated received signals (Sin), in which the bandpass filtered received signal (Bout) is demodulated, and a switching process is triggered with the demodulated received signal (Dout), characterized in that a quality reduction of the bandpass filter (23) is correlated with the switching process.
Method according to one of the preceding claims, characterized in that for the demodulation, the bandpass filtered received signal (Bout) in the form of pulse signals (Compsig) is quantized and these pulse trains are integrated up over their pulse pauses to an integral value.
Method according to one of the preceding claims, characterized in that, before the bandpass filtering, the received signal is subjected to an automatic gain control dependent on a regulating value determined by the signal magnitude of the received signal and the surrounding ambient environmental conditions.
Circuit arrangement for carrying out the method according to one of the preceding claims, characterized in that the receiver circuit comprises an input amplifier (1), to which a regulating amplifier (21) and the bandpass filter (23) are connected thereafter in circuit, whereby the bandpass filter (23) is constructed as a filter of the second order according to the following transfer function F(s):
Dependencies are inferred from the claim text.