Noise reduction in infrasound detection

An apparatus for detecting pressure variations, comprising:

• a sensing circuit, comprising,
• at least two pressure sensors electrically coupled in parallel, wherein at least one of the pressure sensors has a differential input and a differential output,
• a first switching mechanism electrically coupled to the differential input of the at least one pressure sensor, the first switching mechanism is configured to electrically couple a first current source to the at least one pressure sensor according to a first reference signal,
• a resistor electrically coupled to the first switching mechanism, wherein the resistor is configured to provide a resistance that varies based on changes in temperature, and
• a second switching mechanism electrically coupled to the differential output of the at least one pressure sensor, the second switching mechanism is configured to electrically couple a second current source to the at least one pressure sensor according to a second reference signal;
• a manifold configured to receive a pressure and communicate the pressure to the at least two pressure sensors;
• and
• a reference chamber configured to provide a reference pressure to the at least two pressure sensors.

A method for detecting pressure variations, comprising:

• providing a power supply to at least two pressure sensors based on a first reference signal, wherein the at least two pressure sensors are electrically coupled in parallel;
• receiving a differential signal from the at least two pressure sensors;
• neutralizing, based on a second reference signal, an alternating current offset voltage of the differential signal;
• and
• amplifying the neutralized differential signal, wherein amplifying the neutralized differential signal comprises,
• receiving the neutralized differential signal from the at least two pressure sensors, and
• amplifying a difference between a voltage of a first signal of the neutralized differential signal and a voltage of a second signal of the neutralized differential signal.

A circuit for detecting pressure variations, comprising:

• at least two pressure sensors electrically coupled in parallel, wherein at least one of the pressure sensors comprises a differential input and a differential output, wherein the at least two pressure sensors comprise a set of resistors configured as a Wheatstone bridge, wherein at least one of the resistors of the set of resistors is configured to provide a resistance that varies based on changes in pressure upon the at least one of the resistors;
• a first switching mechanism electrically coupled to the differential input of the at least one pressure sensor, the first switching mechanism is configured to electrically couple a first current source to the at least one pressure sensor according to a first reference signal;
• and
• a second switching mechanism electrically coupled to the differential output of the at least one pressure sensor, the second switching mechanism is configured to electrically couple a second current source to the at least one pressure sensor according to a second reference signal, wherein the first reference signal and the second reference signal are phase locked.

A method for detecting pressure variations, comprising:

• providing a power supply to at least two pressure sensors based on a first reference signal, wherein the at least two pressure sensors are electrically coupled in parallel, wherein providing the power supply to the at least two pressure sensors comprises alternating, based on the first reference signal, between providing a current source to a first differential input of the at least two pressure sensors and providing the current source to a second differential input of the at least two pressure sensors;
• receiving a differential signal from the at least two pressure sensors;
• neutralizing, based on a second reference signal, an alternating current offset voltage of the differential signal;
• and
• amplifying the neutralized differential signal.

A method for detecting pressure variations, comprising:

• providing a power supply to at least two pressure sensors based on a first reference signal, wherein the at least two pressure sensors are electrically coupled in parallel, providing a power supply to at least two pressure sensors comprises providing a temperature compensating power supply based on a resistor configured to change resistance based on a change in temperature;
• receiving a differential signal from the at least two pressure sensors;
• neutralizing, based on a second reference signal, an alternating current offset voltage of the differential signal;
• and
• amplifying the neutralized differential signal.

A method for detecting pressure variations, comprising:

• providing a power supply to at least two pressure sensors based on a first reference signal, wherein the at least two pressure sensors are electrically coupled in parallel, wherein the at least two pressure sensors comprise a set of resistors configured as a Wheatstone bridge, wherein at least one of the resistors of the set of resistors is configured to provide a resistance that varies based on changes in pressure upon the at least one of the resistors;
• receiving a differential signal from the at least two pressure sensors;
• neutralizing, based on a second reference signal, an alternating current offset voltage of the differential signal wherein the first reference signal and the second reference signal are phase locked;
• and
• amplifying the neutralized differential signal.

A method for detecting pressure variations, comprising:

• providing a power supply to at least two pressure sensors based on a first reference signal, wherein the at least two pressure sensors are electrically coupled in parallel;
• receiving a differential signal from the at least two pressure sensors;
• neutralizing, based on a second reference signal, an alternating current offset voltage of the differential signal, wherein neutralizing, based on the second reference signal, the alternating current offset voltage of the differential signal comprises providing feedback to null an offset directly at the at least two pressure sensors, and wherein amplifying the neutralized differential signal is optimized for high gain and low noise;
• and
• amplifying the neutralized differential signal.