Delay lines are an elementary electronic component of countless circuits and complicated devices. Circuit designers make use of this fundamental building block in numerous applications ranging from acoustic propagation delay to optical coherence tomography.
Despite being ridiculously common, most people don’t know the first thing about delay lines. To address this issue and to increase awareness about delay lines, we’ve compiled a short guide that explains what they are and why they matter so much in today’s day and age.
What are Delay Lines?
Simply put, a delay line is an electrical component that can delay an analog signal with respect to time. Depending on the application they’re used for, this behavior of delay lines can be applied to countless devices.
While delay lines may have surged in popularity in recent years, we’ve been using them for countless years for various reasons. It’s a well-documented fact that one of the earliest computers ever invented (in 1949) relied on this component!
We’re of course talking about the EDSAC (Electronic Delay Storage Automatic Calculator) that used mercury-filled delay lines as storage units. Because the acoustic impedance of mercury is similar to that piezoelectric quartz crystals, circuit designers were able to minimize energy losses by using mercury-filled delay lines!
Types of Delay Lines with respect to Signals:
As far as signals are concerned, there are two main types of delay lines, namely;
1.Analog Delay Lines:
Analog Delay Lines (ADL) are sometimes referred to as passive delay lines. They are constructed using analog components and can handle both digital and analog signals. By using fundamental electrical components such as capacitors and inductors, ADLs can even attenuate the signal from the input to output terminal.
2.Digital Delay Lines:
Digital Delay Lines (DDL) are more commonly known as active delay lines. Unlike their analog counterparts, they can’t handle analog signals and can only work with digital signals. They’re made completely from digital components and therefore can’t attenuate the signal from the input terminal to the output terminal. Complementary Metal-Oxide Semiconductor (CMOS) is by far the most widely known and commonly used DDL logic family.
Types of Delay Lines with respect to Delay Capabilities:
As far as the time delay is concerned, there are two main types of delay lines, namely;
1.Fixed Delay Lines:
As its name suggests, a fixed delay line has fixed delay period. This delay period is set by the manufacturer of the product and can never be edited or changed by the circuit designer. Fixed delay lines are cheaper and more difficult to use than variable delay lines.
2.Variable Delay Lines:
Unlike their fixed counterparts, variable delay lines are much more commonly used as they allow the circuit designer to change the magnitude of the time of delay. That being said, it should be noted that these delay lines don’t have an infinite range as the value of delay can be varied between two limits set by the manufacturer.
Important Delay Line Specifications:
Now that we understand what delay lines are, how they work, and why they matter, it’s time we turn our attention to selecting an option that will work in your circuit. In order to ensure that you get the delay line that’s compatible with your electrical network, you need to be aware of three important factors or specifications, namely;
1.Line Type (whether you want a fixed or a variable delay line that can handle analog signals or digital signals, etc.)
2.Rise Time (rise time is generally defined as the time taken for the magnitude to rise from 10% to at least 90% of its final amplitude)
3.Time Delay (the units of time by which a delay line can slow down a signal)
We’re confident that if you take these factors into consideration when searching for a delay line, you can easily find an option that’s compatible with your circuit. We at ADSANTEC also maintain a large collection of narrowband and broadband variable delay lines.
Our online store also includes the likes of high speed analog to digital convertors, active power dividers, and much more! Browse through our selection of electrical solutions to design your desired electrical networks!