The Engineer Who Built the World’s Fastest Pulse Generator

In 1977, UCLA professor Dr. Siegfried Knorr built a pulse generator faster than Hewlett Packard could produce. This is the founding story of Colby Instruments and the electromechanical trombone patent that changed precision electronics.

In 1977, an electrical engineering professor at UCLA had a problem. He had built the world’s fastest rise-time pulse generator, faster than anything Hewlett Packard could produce. He did not know what to do with it. So, he started a company and waited to see who needed it.

That company was Colby Instruments. And nearly five decades later, it is still building instruments that nobody else in the world can replicate.

A professor with a problem

Dr. Siegfried Knorr had spent his career working at the edge of what electronics could do. Before UCLA, he had worked at companies including Tektronix, developing expertise in high-frequency electronics and radio technology. Analog electronics was his domain, and he was, by any measure, exceptional at it.

His pulse generator was the proof. A pulse generator produces electromagnetic pulses, and the figure that matters is rise time: how quickly the signal gets from baseline to target voltage. In practical terms, how sharp is the edge of the wave? Knorr’s device got there faster than anything commercially available at the time, reaching up to one billion operations per second, or one gigahertz, with a rise time that the industry leader could not match.

He had built something genuinely world-class. Academia, with its constraints and its modest rewards, no longer seemed the right setting for it. In Santa Monica in 1977, he set up Colby Instruments as a research and development operation and began to find out what the market would make of what he had created.

As it turned out, the market came to him.

The market that found him

Santa Monica in the late 1970s was surrounded by aerospace and defence. Hughes Aircraft, TRW, and a cluster of other major contractors were nearby, and the test and measurement industry had a genuine need for instruments that could push signals faster and more precisely than anyone had managed before. Knorr’s pulse generators went into electronics testing, computer manufacture, defence systems, and the aerospace supply chain.

He did not chase this market down. It arrived. The instrument manufacturers and defence contractors needed what he had built, and word moved through the industry accordingly. By the 1980s, Colby was advertising in specialist publications including Microwave and RF Journal, and a loyal customer base was forming around the quality of what the company produced.

The patent that changed everything

Pulse generators were a strong product line, but the innovation that would define Colby’s long-term identity came in the late 1980s, when Knorr was granted a patent for what is known as the electromechanical trombone.

The name is precise. A trombone, in electronics, is a mechanical structure that changes the path length of a high-frequency signal. Because the speed of the signal is fixed, changing how far it travels changes how long it takes to arrive. Extend the path, and the signal arrives later. Shorten it, and it arrives sooner.

This matters for two related reasons. In timing applications, it gives engineers the ability to introduce a controlled, variable delay into a signal chain. In RF and microwave work, where cycles repeat at a billion times per second, that same delay represents a phase shift, a movement along the 360-degree cycle of the signal.

Knorr’s innovation was not the trombone itself, which was an established concept in high-frequency electronics. His contribution was the automation of the mechanism: adding a motor to the trombone so that path length could be varied electronically, under programme control, rather than by hand.

That sounds straightforward. In practice, at these frequencies, the physics involved is unforgiving. Precision in movement, precision in distance, and precision in how the signal interacts with the path at every point along the way are all critical. The quality, range, and repeatability of the delay depend on engineering choices that are painstaking to get right and genuinely difficult to replicate.

This is why, as Victor Chinn, who now runs Colby Instruments, explains, no other company in the world can do what Colby’s technology does.

From academia to an industry of one

The programmable delay line that grew out of the trombone patent found its market through the 1990s in phase noise analysis. HP built systems to measure the phase noise quality of high-frequency devices, and those systems needed an instrument capable of shifting signal phase with high precision. Colby’s electromechanical delay line was that instrument.

Telecom customers followed. As the telecoms boom accelerated in the late 1990s and early 2000s, companies including Nortel Networks were buying units repeatedly, month after month. The demand was real, and Colby grew with it.

Then Knorr’s health declined, rapidly and irreversibly. He had developed Creutzfeldt-Jakob disease, and by late 2004, he could no longer run the business. Victor Chinn, his son-in-law, stepped in and purchased the assets of Colby in early 2005, relocating the company from Santa Monica to Bellevue, Washington. He arrived with a background in digital electronics rather than analog, a deep respect for what Knorr had built, and a clear-eyed understanding that the company would need to evolve if it was to survive.

The product line Chinn inherited was hand-built, painstakingly engineered, and dependent on analogue expertise that could not simply be replaced. What followed was a careful process of modernisation: new CPUs, Ethernet connectivity, improved positional accuracy through software algorithms, and more efficient production methods. The PDL series arrived in 2007. The X series followed in 2020 and 2021. And the development of a digital pin-diode delay line, initially prompted by a request from Northrop Grumman to replicate modules Knorr had built by hand, opened an entirely new product direction.

Why provenance matters in precision instruments

The history of Colby Instruments is not just a heritage story. It is a trust signal.

Procurement managers and engineers buying into test and measurement, aerospace, defence, or telecommunications infrastructure need to know that the equipment they are specifying comes from somewhere. That it reflects genuine engineering depth rather than a rebranded commodity. That when they need a component to operate within femtoseconds of accuracy, the company behind it has built that capability over decades, not months.

Colby Instruments has a Colby Instruments history that stretches back to Santa Monica in 1977, to a professor who built something faster than Hewlett Packard and did not yet know what to do with it. The programmable delay line history running through the company connects Knorr’s original patent to the instruments being shipped from Bellevue today. The electromechanical trombone patent that forms the core of the company’s identity has never been replicated elsewhere.

That is a strong foundation. And it is, in the end, why the market keeps finding Colby Instruments, just as it found Siegfried Knorr all those years ago. Colby Instruments remains the industry leader in high-precision programmable delay line instruments. Find us online or get in touch to discuss your requirements.