Arrangement for the wireless transmission of measuring signals

An arrangement including a sensor and an evaluating unit for the wireless transmission of at least one measuring signal from said sensor and to said evaluating unit by a pair of first electrical coils that are at least temporarily inductively coupled with one another, said sensor being supplied with energy by said evaluating unit via a second pair of electrical coils including primary and secondary coils and connected to said evaluating unit that are temporarily inductively coupled with one another, wherein said sensor includes a power supply circuit means connected to said second pair of electrical coils for receiving a low-frequency energy signal from said second pair of electrical coils for supplying an energy signal to a transmitting oscillator mean, and transmitting oscillator means responding to at least one measured physical quantity and providing a medium frequency measurement signal to be transmitted over said first pair of electrical coils to said evaluating unit, wherein:

• the frequency of said energy supply signal transmitted between said second pair of electrical coils is below 10 kc/s;
• said power supply means has at least one secondary oscillating circuit with means for adjusting said secondary oscillating circuit to the frequency of an energy supply signal supplied by said second pair of electrical coils;
• said secondary oscillating circuit includes a capacitor connected in parallel to said secondary coil which is connected in parallel to a rectifier bridge that has a filter capacitor as its diagonal bridge;
• wherein said sensor is arranged on a machine part which rotates relative to a coupling part which is arranged on a stationary part of the machine;
• and
• wherein said high-frequency receiver is comprised of a variable capacitor connected in parallel with said receiver coil and with said receiver coil forms a receiver oscillating circuit;
• a high-frequency filter connected to said variable capacitor;
• a high-frequency amplifier connected to said high-frequency filter, and a rectifier connected to said high frequency amplifier, said rectifier having a filter capacitor, and a comparator means connected to said filter capacitor for comparing the voltage at said filter capacitor with a reference voltage.