Francis H Hilbert

Title: Inventor Francis H. Hilbert: A Pioneer in Stereo Broadcast System Technology

Introduction

Francis H. Hilbert, an accomplished inventor based in Addison, IL, has made significant contributions to the field of audio technology. With a total of 12 patents to his name, Hilbert's work showcases his innovative spirit and technical expertise in developing advanced audio systems.

Latest Patents

Among his notable inventions, Hilbert's recent patent for a **Stereo Broadcast System** stands out. This system features a signal transmitted as a compatible amplitude-modulated carrier, with amplitude directly proportional to the monaural information, or 1+L+R, which extends to frequencies near the upper end of the normal program spectrum. Beyond a specific transition region, the amplitude becomes a pure quadrature function, with instantaneous phase varying as a function of the quadrature phase relationship. The patent discloses both transmitter and receiver embodiments that enhance audio performance.

Another significant contribution is his patent for a **Phase Locked Loop with Improved Lock-in**. This innovative circuit determines whether an incoming frequency falls within the normal "lock-in" range of a phase-locked loop voltage-controlled oscillator (VCO). If the incoming frequency is outside this range, the circuit rectifies and gates the beats to provide a DC control voltage that locks the oscillator onto the incoming frequency. This circuit, suitable for signals of any waveform including quadrature signals and AM stereophonic signals, features half or full wave rectification as needed and bandwidth control.

Career Highlights

Hilbert's professional journey includes pivotal roles at renowned companies such as Motorola Corporation and Matsushita Electric Company of America. His experience in these leading firms has significantly influenced his approach to audio technology, allowing him to develop innovative solutions for complex audio challenges.

Collaborations

Throughout his career, Hilbert has collaborated with esteemed professionals in the field, including Norman W. Parker and Theodore S. Rzeszewski. These partnerships have enriched his work and fostered an environment of innovation and creativity.

Conclusion

Francis H. Hilbert's contributions to audio technology through his inventions have left a lasting impact on the industry. His advancements in stereo broadcasting and phase-locked loop technology illustrate his dedication to pushing the boundaries of innovation. With a track record of successful collaborations and a strong career foundation, Hilbert continues to inspire future generations of inventors and engineers.