Abstract: A circuit for conditioning an acoustic transducer driving signal includes an inner feedback circuit having a test signal input for receiving a test signal, a feedback input for receiving a feedback signal, circuitry for forming an output signal including circuitry for amplifying the input signal according to the feedback signal, and an output for providing the output signal. The circuit also includes an outer feedback circuit having a signal input for receiving the output signal from the inner feedback circuit, a desired offset input for receiving a signal representative of a desired output offset, a first low-pass filter circuit for detecting an actual offset in the output signal, signal combination circuitry for forming the feedback signal including combining the actual offset with the desired output offset, and a feedback output for providing the feedback signal to the feedback input of the inner feedback circuit.

Abstract: A circuit for conditioning an acoustic transducer driving signal includes an inner feedback circuit having a test signal input for receiving a test signal, a feedback input for receiving a feedback signal, circuitry for forming an output signal including circuitry for amplifying the input signal according to the feedback signal, and an output for providing the output signal. The circuit also includes an outer feedback circuit having a signal input for receiving the output signal from the inner feedback circuit, a desired offset input for receiving a signal representative of a desired output offset, a first low-pass filter circuit for detecting an actual offset in the output signal, signal combination circuitry for forming the feedback signal including combining the actual offset with the desired output offset, and a feedback output for providing the feedback signal to the feedback input of the inner feedback circuit.

Abstract: An dental imaging apparatus and a corresponding method is disclosed. The imaging apparatus includes an image sensor, a lamp for providing illumination, and an image processor for processing the image in accordance with either a first stored white balance related to a characteristic of the lamp illumination or a second stored white balance. Preferably, the first stored white balance is used when the lamp is on, and the second stored white balance is used when the lamp is off.

Abstract: A handheld dental video camera and a corresponding method is disclosed. The dental video camera includes a window for receiving light. In some aspects of the invention, a lamp is mounted distally beyond the window and aimed to illuminate a subject. In other aspects of the invention, a white LED is used to illuminate the subject.