Synchronous demodulation with precision track-and-hold circuit
First Claim
Patent Images
1. A synchronous demodulation circuit arrangement comprising:
- a sensor interface circuit coupled to receive a sensor signal, the sensor interface circuit associated with a propagation delay;
a microcontroller configured to generate a microcontroller timing signal and to adjust timing of the microcontroller timing signal as a function of the propagation delay; and
a track-and-hold circuit arrangement coupled to receive the sensor signal and responsive to the microcontroller timing signal, the track-and-hold circuit arrangement configured to periodically sample the sensor signal;
wherein the microcontroller is configured to detect a peak amplitude of the sensor signal and generate a hold control signal in response to the detected peak amplitude and the track-and-hold circuit arrangement is configured to output a peak indication signal in response to the hold control signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A synchronous demodulation circuit uses a digitally controlled track-and-hold circuit to capture the peak amplitude of a rectified signal. A microcontroller controls the track-and-hold circuit. In particular, the microcontroller controls a hold mode of the track-and-hold circuit to capture the peak amplitude of the rectified signal.
-
Citations
32 Claims
-
1. A synchronous demodulation circuit arrangement comprising:
-
a sensor interface circuit coupled to receive a sensor signal, the sensor interface circuit associated with a propagation delay; a microcontroller configured to generate a microcontroller timing signal and to adjust timing of the microcontroller timing signal as a function of the propagation delay; and a track-and-hold circuit arrangement coupled to receive the sensor signal and responsive to the microcontroller timing signal, the track-and-hold circuit arrangement configured to periodically sample the sensor signal; wherein the microcontroller is configured to detect a peak amplitude of the sensor signal and generate a hold control signal in response to the detected peak amplitude and the track-and-hold circuit arrangement is configured to output a peak indication signal in response to the hold control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An occupant detection system comprising:
-
a sensor configured to generate a sensor signal in response to sensing a vehicle occupant; a sensor interface circuit coupled to receive the sensor signal, the sensor interface circuit associated with a propagation delay; a microcontroller configured to generate a microcontroller timing signal and to adjust timing of the microcontroller timing signal as a function of the propagation delay; and a track-and-hold circuit arrangement coupled to receive the sensor signal and responsive to the microcontroller timing signal, the track-and-hold circuit arrangement configured to periodically sample the sensor signal; wherein the microcontroller is configured to detect a peak amplitude of the sensor signal and generate a hold control signal in response to the detected peak amplitude and the track-and-hold circuit arrangement is configured to output a peak indication signal in response to the hold control signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A method to demodulate a signal received via an interface circuit, the method comprising:
-
synchronizing a microcontroller to a drive signal at least in part by detecting an edge of the drive signal; adjusting a microcontroller timing signal as a function of a propagation delay of the interface circuit; detecting a peak amplitude of the signal received via the interface circuit; in response to detecting the peak amplitude, generating a hold control signal as a function of the adjusted microcontroller timing signal; and generating a peak indication signal in response to the hold control signal. - View Dependent Claims (19, 20, 21)
-
-
22. A method to detect a vehicle occupant, the method comprising:
-
generating a sensor signal in response to sensing a vehicle occupant; providing the sensor signal to a demodulation circuit arrangement via an interface circuit; synchronizing a microcontroller to a sensor drive signal at least in part by detecting an edge of the sensor drive signal; adjusting a microcontroller timing signal as a function of a propagation delay of the interface circuit; detecting a peak amplitude of the sensor signal; in response to detecting the peak amplitude, generating a hold control signal as a function of the adjusted microcontroller timing signal; and generating a peak indication signal in response to the hold control signal. - View Dependent Claims (23, 24, 25, 26, 27, 28)
-
-
29. A microcontroller-readable medium having microcontroller-executable instructions that, when executed by a microcontroller, cause the microcontroller to:
-
synchronize the microcontroller to a drive signal at least in part by detecting an edge of the drive signal; adjust a microcontroller timing signal as a function of a propagation delay of an interface circuit; detect a peak amplitude of a signal received via the interface circuit; and in response to detecting the peak amplitude, generate a hold control signal as a function of the adjusted microcontroller timing signal. - View Dependent Claims (30, 31, 32)
-
Specification