John D Schilling

Title: John D. Schilling: Television Signal and Frequency-Control Innovations.

Introduction.

John D. Schilling is an inventor associated with Dresher, Pennsylvania. His patent work includes television technologies for protecting audio signals and maintaining frequency control. He holds 3 patents.

Latest Patents.

**Method of Providing Sound Privacy System Compatible with Mono and BTSC.** This invention describes a way to restrict unauthorized access to the audio portion of a television signal. It modulates the audio using a nonstandard 4.75 MHz carrier, offset from the standard 4.5 MHz carrier, and adds an unmodulated 4.5 MHz carrier to prevent standard television receivers from receiving the offset audio.

**Automatic Frequency Control.** This invention tracks a television signal before and after an interruption. A voltage-controlled feedback loop uses an oscillator, mixer, filter, and detector to track a selected signal component. When that component disappears, circuitry applies a reference voltage to the oscillator; when the signal returns, the detector can resume tracking it.

Career Highlights.

Schilling’s listed company affiliations include General Instrument Corporation and its Jerrold Division. His patent work reflects contributions to television signal processing and receiver circuitry.

Collaborations.

His listed coworkers include Daniel J. Marz and Joseph Dolinski, reflecting professional connections in the television technology field.

Conclusion.

John D. Schilling’s patents address practical challenges in television audio privacy and frequency tracking, highlighting his contributions to broadcast and receiver technology.