Engineers Serving Engineers: Building Reliable Equipment to Power Innovation


I'm an engineer, so I love innovation. As the head of Colby Instruments, I don't see myself as a salesman, but as a partner who helps others design the future. A Harvard marketing professor once said, "People don't want to buy a quarter-inch drill. They want a quarter-inch hole." I build highly advanced precision instruments that help engineers test complex electronic circuits.

My father-in-law, Dr. Siegfried Knorr, founded Colby Instruments in 1977. He was an electrical engineering professor at UCLA, who grew tired of the limited opportunities in the academic world.  He designed Colby’s  first instruments—high-frequency pulse generators that outperformed the competition of the time, including offerings by HP, the predecessor of Keysight Technologies.

In 1990, he patented an electromechanical trombone: a sliding interconnect of tubes that uses a programmable stepper motor to vary the length of the physical signal path, thus delaying the signal's transmission when measured from one end to the other. He called this device a programmable delay line, and it has been our primary product ever since. Our incredibly precise stepper motor can delay a signal from 0 to 100 nanoseconds (depending on the model) at step intervals to one half a billionth of a second—or half a picosecond. Delaying an RF wave signal in this way may seem like a frivolous pursuit, but it has practical applications in the world of engineering. Colby Instruments partnered with some very prestigious customers who need this kind of tool.

Powering the World’s Biggest Companies 


One of the sectors we serve is the aerospace industry, specifically the manufacturing and testing of radar equipment by bouncing radio signals off airplanes in flight to see how far away they are. The longer it takes for the signal to return, the farther away the aircraft. 

When you're building hundreds of thousands of radar units every year, you can't test them all by attempting to measure the distance of physical objects. That's where we come in. Radar builders use our programmable delay line instruments to simulate bouncing signals off aircraft and to test individual units for accuracy as they roll off the assembly line. 

Companies like Qualcomm and Intel use our instruments to validate and verify new semiconductor chip designs. They test tolerances by delaying the arrival of signals to ensure that they are still processed if the timing is off. Tektronix incorporated our trombone into a new product that tests the timing of video signals to ensure that they comply with the latest version of the HDMI reference standard. Skyworks performs intermodulation distortion (IMD) tests with our instruments. Particle Accelerator Labs all around the world use our instruments for precision timing and synchronization applications. 

Testing the Accuracy of Our Test Equipment

Our programmable delay lines are precise and elegant. Though delaying a signal is a matter of simple physics, there is a great deal that our customers can accomplish with our trombone, especially in testing environments. While Colby Instruments helps our customers guarantee the accuracy of their products, how do we guarantee the accuracy of ours?

That's where Keysight comes in. Like any other instrument used in testing and measurement environments, our programmable delay lines have to be set up and calibrated to ensure our customers can make accurate measurements. Keysight’s E5063A vector network analyzer (VNA) helps us adjust the precision and accuracy of our products. 

The testing procedure is simple. I route an RF signal through the trombone, use the stepper motor to vary the delay, and then measure the phase degree at each end of the trombone. By comparing the phase degree measurements to the physical length of the signal transmission path through the trombone, I can then calculate the delay time.


In this way, I can fine-tune the movement of the stepper motor to set the proper time intervals and determine the overall accuracy of each one of our programmable delay lines. When I say our equipment is accurate to half-a-billionth of a second, I can back it up with test results from our Keysight VNA.

A Small Investment with Big Returns

A vector network analyzer is a very specialized piece of equipment. There are only a few manufacturers of such products on the planet. I could have gone with the competition, but I've come to trust Keysight over the years. The build quality and the level of support are second to none, and Keysight is also first out of the gate with many high-end features.

Years ago, we used time-domain reflectometers (TDRs) to test our equipment, but VNAs started to gain mainstream acceptance and they also operated at higher frequencies. At the time, Keysight's predecessor, Agilent, made the best, most affordable, and most accurate VNAs, so we went with them.

The name may have changed, but the quality and accuracy remain. Vector network analyzers don't come cheap. Our E5063A set us back some $20,000, but it has paid for itself many times over. We’ve produced many, many hundreds of our programmable delay lines over the years.  By using Keysight solutions, I’ve received at least a 10x return on my investment. 

Selling Results Instead of Planned Obsolescence

I have to be honest; Colby Instruments is a labor of love. I reverse inherited the company from my father-in-law in 2004. If I had wanted to, I could have retired long ago. As a matter of fact, I'm semi-retired right now, but I see the utility of our products and I want to get our gear into the hands of engineers.

I believe in our programmable delay lines because they don't fail. They're old-school mechanical designs that need the occasional tune-up because parts of the trombone wear out, but they can last for many years. I’m not in the business of planned obsolescence. I don’t want my customers coming back to me because our products have a limited lifespan. I’d rather have them buy more of our devices so they can do more testing.

I've also addressed the issue of wear by patenting and marketing a solid-state version our programmable delay line that uses PIN diode switching technology, but the step resolution is only to one picosecond, which can limit its application. 

A Reciprocal Partnership


I am also pleased that Keysight sends so much business our way. We make a programmable delay line as a phase shifter that can be used with Keysight’s N5511A Phase Noise Test System. Our delay line enables the user to establish quadrature between signal paths. This is necessary when measuring additive phase noise on two-port devices such as amplifiers or multipliers. 

Customers often like the convenience of our phase shifter because they are electronically tunable and thus the measurement can be automated. In the past, we were the OEM for this part, but now we sell our programmable delay lines directly to Keysight's customers after they have purchased a noise analyzer.  There is no alternative in the marketplace for a programmable phase shifter with such high precision and signal bandwidth. 

Having the support of a leading supplier of testing and measurement equipment like Keysight helps promote our brand, but we already have plenty of name recognition, despite the fact we do little advertising. All this is a testament to the quality and the utility of our unique products.

I am proud of the partnerships we've developed over the years at Colby. A few weeks ago, I traveled to CERN in Switzerland, which is home to the Large Hadron Collider. This massive particle accelerator is helping to unravel the secrets of the universe, and our programmable delay lines will be playing a small part. CERN engineers will be using our gear to test a new design for the thousands of sensors that are used to detect subatomic particle collisions. These chips are helping to push the boundaries of human knowledge, but this is all in a day's work for me.

When I do retire, I will be secure knowing that I’ve helped contribute to a better, brighter future. Keysight is helping Colby Instruments and engineers around the world build the world of tomorrow.