DR. ERIC EDWIN JACOBSEN, DDS
Dentist at 19 Ave, Phoenix, AZ

5361048, Nov 1, 1994

Aug 30, 1993

8/113007

Jeffery I. Baum - Scottsdale AZ
Eric S. Jacobsen - Phoenix AZ

Motorola, Inc. - Schaumburg IL

H03C 300, G08C 1900, G08C 1916, H03K 708

332109

A pulse width modulator generates a linear sawtooth ramp waveform from a pulse signal to compare against an amplified input signal derived from a transducer output voltage signal. A first circuit generates the linear ramp waveform in response to the pulse signal. First and second amplifiers receive the differential transducer signal and provide the amplified input signal to one input of a comparator. The comparator has another input receiving the linear ramp waveform, and an output for providing a pulse width modulated output signal having a duty cycle proportional to the differential transducer signal. If the amplified input signal is greater than the sawtooth ramp then the output signal of the pulse width modulator goes to one state; otherwise, the output signal goes to an opposite state. The pulse width of the output signal is thus linearly proportional to the amplitude of the transducer output signal. A microcontroller uses a single time base to generate the pulse signal and measure the pulse width of the output signal to determine the reading from the transducer.