Amplitude stabilized oscillator circuit

专利名称：Amplitude stabilized oscillator circuit发明人：Wolfgang Mann,Horst Schaefer申请号：US08/858611申请日：19970521公开号：US05801592A公开日：19980901

摘要：An oscillator circuit is provided for stabilizing the amplitude of a HF oscillationof an audio signal. In such an oscillator circuit, an audio signal having a frequency in therange of 20 Hz . . . 20 kHz is coupled into the oscillator circuit, is modulated with a highfrequency and is emitted in the form of an RF audio signal having a frequency of morethan 2 MHz. Such an oscillator circuit is used for instance in an infrared transmitting unit,wherein a low frequency audio signal is transformed into a higher frequency infraredsignal. The higher frequency audio signals are transmitted via infrared channel to anappropriate receiving unit--for instance to infrared head phones--which comprises areceiving unit having an appropriate demodulator and preferably also a stereo-decoderin order to reproduce the low frequency audio signals. The oscillator for stabilizing theamplitude of a high frequency oscillation comprises a resonant circuit which is coupledwith a first transistor having a base terminal, an emitter contact, and a collector contact.The first transistor develops an output voltage at the emitter contact which is fed backinto a base circuit of the first transistor. The collector contact of the first transistor iscoupled to a supply voltage source. The supply voltage source is coupled to the baseterminal of the first transistor via a resistor. The emitter contact of the first transistor iscoupled with the base terminal of a second transistor. The second transistor has a

collector contact which is connected to the base terminal of the first transistor forcontrolling the voltage at the base terminal of the first transistor.

申请人：SENNHEISER ELECTRONIC GMBH & CO. KG

代理机构：McAulay Fisher Nissen Goldberg & Kiel, LLP

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