Load testing circuit
AssigneeHarman Becker Automotive Systems GmbH
InventorArnold Knott
Life of this patent
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Abstract
A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load impedance, an energy-storing element being connected to the second terminal of the load impedance and providing an output signal, and a measuring unit that measures the output signal or compares the output signal with a reference.
Claims8
A loudspeaker load testing circuit for detecting the impedance of a loudspeaker, the loudspeaker load testing circuit comprising:
- a loudspeaker having a first terminal and a second terminal;
- a test signal generator that is connected to the first terminal of the loudspeaker to provide a test signal of a defined bandwidth to the first terminal of the loudspeaker;
- an energy-storing element having a first element lead connected to the second terminal of the loudspeaker and a second element lead connected to a reference voltage;
- and
- a measuring unit that compares an output signal value at the second terminal of the loudspeaker to determine if the output signal value exceeds a threshold value,
- where the test signal generator comprises a microcontroller, and an amplifier that provides the drive signal,
- where the test signal generator further comprises a signal shaping circuit connected to an output pin of the microcontroller for providing the test signal.
A loudspeaker load testing circuit for detecting the impedance of a loudspeaker, the loudspeaker load testing circuit comprising:
- a loudspeaker having a first terminal and a second terminal;
- a test signal generator that is connected to the first terminal of the loudspeaker to provide a test signal of a defined bandwidth to the first terminal of the loudspeaker;
- an energy-storing element having a first element lead connected to the second terminal of the loudspeaker and a second element lead connected to a reference voltage;
- and
- a measuring unit that compares an output signal value at the second terminal of the loudspeaker to determine if the output signal value exceeds a threshold value, where the measurement unit comprises a threshold detector,
- where the threshold detector comprises a Schmitt-Trigger.
A loudspeaker load testing circuit for detecting the impedance of a loudspeaker, the loudspeaker load testing circuit comprising:
- a loudspeaker having a first terminal and a second terminal;
- a test signal generator that is connected to the first terminal of the loudspeaker to provide a test signal of a defined bandwidth to the first terminal of the loudspeaker;
- an energy-storing element having a first element lead connected to the second terminal of the loudspeaker and a second element lead connected to a reference voltage;
- and
- a measuring unit that compares an output signal value at the second terminal of the loudspeaker to determine if the output signal value exceeds a threshold value, where the measurement unit comprises a threshold detector,
- where the threshold detector comprises a window-comparator.
A loudspeaker load testing circuit for detecting the impedance of a loudspeaker, the loudspeaker load testing circuit comprising:
- a loudspeaker having a first terminal and a second terminal;
- a test signal generator that is connected to the first terminal of the loudspeaker to provide a test signal of a defined bandwidth to the first terminal of the loudspeaker;
- an energy-storing element having a first element lead connected to the second terminal of the loudspeaker and a second element lead connected to a reference voltage;
- and
- a measuring unit that compares an output signal value at the second terminal of the loudspeaker to determine if the output signal value exceeds a threshold value,
- where the test circuit is switchable to different load impedances of different amplifiers by multiplex-switches.
Dependencies are inferred from the claim text.