Circuit for separating the output of an oscillator from the other parts of a mobile communication system

Mobile communication system having a number of parts comprising;

• an oscillator circuit with an oscillator and a first circuit element for separating the output of the oscillator from the other parts of the mobile communication system, the input of the first circuit element being coupled to the oscillator;
• a second circuit element by which the input of said first circuit element is coupled to the oscillator, said second circuit element having an adjustable impedance;
• and
• an adjusting element arranged to adjust the impedance of said second circuit element according to the alternating voltage level effective at the output of said first circuit element in order to minimize the loading effect of said first circuit element on the oscillator when there is a certain desirable alternating voltage level effective at the output of the first circuit element.

An oscillator circuit, connected with other parts in a communication system, comprising:

• an oscillator having an output;
• a first circuit element, having an input coupled to said oscillator output, for separating said oscillator output from the other parts of the communication system;
• a second circuit element, having an adjustable impedance, with an input connected to said oscillator output and an output connected to said input of said first circuit element;
• an adjusting element for adjusting the impedance of said second circuit element in response to the signal level effective at the output said first circuit element;
• an amplifier stage in said first circuit element for producing the separation of the output of said oscillator from the other parts of the communication system;
• and
• a diode detector, coupled as a voltage multiplier in said adjusting element, for producing an adjusting control signal in accordance with the signal level effective at the output of the first circuit element.