How Do Vehicle Collision Avoidance Systems Work?

by Jaymie Murray 11. January 2016 14:32

Imagine that you’re slowly making your way down a dark highway as your wipers struggle to keep up with the downpour that is assaulting your windshield. As you squint to make out the yellow lines painted on the road, a car traveling next to you suddenly changes into your lane and cuts you off. Before you have time to react and hit the brakes, your car automatically slows down, avoiding a serious accident.

This is a common scenario with newer cars fitted with pre-collision avoidance systems. These active safety systems use Doppler radar to detect objects that come into a vehicle’s path, triggering the brakes before impact. Typically, a radar detector is placed towards the front of a vehicle, such as within the grill. This detector sends out high frequency waves and then interprets the signals that bounce back, which would indicate object location, speed, and the direction it is traveling.

In order for the system to process all of this information and take action in a matter of milliseconds, a delay needs to be introduced. Linear Surface Acoustic Wave (SAW) delay lines are typically used in collision avoidance systems because they are smaller and less expensive than other delay line options. SAW delay lines used in collision avoidance systems operate across public frequency bands, and system designers would typically down mix the radar frequencies in order to process them through one channel with a constant delay.

This gives the system all of the information it needs to determine if a collision is imminent, and allows it to respond by automatically deploying the brakes, tensing seatbelts, or taking other safety precautions rapidly enough to avoid impact. 

A version of this post first appeared on Wireless Design & Development

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Infographics | RF/Microwave & Microelectronics

SAW vs. BAW: How the Delay Line Technologies Stack Up

by Jaymie Murray 8. June 2015 08:11

SAW (Surface Acoustic Wave) and BAW (Bulk Acoustic Wave) technologies are widely used in a variety of applications, including filters, oscillators, transformers, and delay lines. SAW and BAW delay lines in particular offer several advantages over other signal wave technologies and are used in a variety of applications, from Electronic Warfare (EW) target generation to communications systems for television and video. While they are used in somewhat similar applications, SAW and BAW technologies are each unique and have distinctive characteristics. Factors such as required signal delay, frequency, footprint, and cost all must be considered when choosing the best delay line solution for a project. 

Both SAW and BAW devices exploit the piezoelectric effect of certain substrate materials such as quartz and lanthanum gallium silicate by using interdigital transducers (IDTs) to convert acoustic waves to electrical signals and vice versa. Delay lines that utilize SAW and BAW are designed to introduce a calculated delay into the transmission of a wave signal. This signal delay could be needed for a variety of reasons. For example, in weather Doppler systems, weather radars emit pulses which track the movement and location of objects such as hailstones and raindrops. BAW delay lines are used to control the timing of these pulses. SAW delay lines provide required delays to synchronize data in communications systems such as television broadcasting. 

In each of these examples, one technology is the best choice over another because of their respective characteristics. SAW delay lines are usually smaller and lighter than BAW delay lines, which gives them a smaller footprint and therefore can make them less expensive. SAW delay lines also typically offer a wide frequency range from 30 to 2000 MHz. However, SAW delay lines can only provide a fairly small delay range of 0.1 to 10 µsec. If a larger delay range is needed, then BAW delay lines, with a typical range of 0.15 to 3000 µsec, are the best option. This can translate into a larger footprint and raise costs somewhat, but the wider delay range allows for increased adaptability and flexibility.  BAW can also be safely used in a wider temperature range than devices that use SAW, making it a more appropriate choice for harsh or extreme conditions. 

While they are both equally reliable and can offer the delays needed for effective wave signal processing, SAW and BAW each have their own distinct advantages. Ultimately, the best delay line option will be the one that most closely meets important project requirements, such as footprint, frequency, cost, and delay time. 

Learn more about API's delay lines, contact us, or request a quote.

This post originally appeared in Wireless Design & Development

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Infographics | RF/Microwave & Microelectronics

Delay Lines Week: Why API's Analog Delay Lines Are the Best Choice over Digital

by Allison Goss 13. March 2015 08:58

While many of API's competitors offer digital delay line options, they have several distinct disadvantages compared to API's analog delay lines. Cost, size, and weight can all be significantly lower with analog delay lines, while still offering higher MTBF (Mean Time Before Failure) rates and reliability. 

Analog vs Digital Delay Lines Why API Technologies' Analog Delay Lines are the Best Choice Analog VS Digital Analog delay lines offer higher reliability and a higher MTBF (mean time before failure) Digital delay lines are less reliable and have a lower MTBF than analog delay lines MTBF MTBF Analog delay lines are more affordable than digital, and they cost less to run and maintain over their lifetime Digital delay lines are more expensive to purchase, and they are more costly to replace and maintain API’s dispersive steel delay lines are smaller and lighter than their digital counterparts Digital delay lines are larger and have a bigger footprint, making them more cumbersome For analog delay lines, less software Digital delay lines require an array of For analog delay lines, less software and systems engineering are needed, and fewer engineering disciplines are required Digital delay lines require an array of software as well as several systems engineering disciplines micro.apitech.com/delay_lines

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RF/Microwave & Microelectronics

Delay Lines Week: Did You Know... API's Delay Lines Have Conductor Spacing as Small as 1/180th of a Human Hair?

by Allison Goss 12. March 2015 15:43

Did you Know?  API has perfected the wafer fabrication technique in our SAW delay lines to achieve conductor spacing down to .6 microns, ( 1/180th of the diameter of the average human hair) which allows for higher frequency delay lines

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RF/Microwave & Microelectronics

Delay Lines Week: Did You Know... API's Delay Lines Offer Delays Below 1 Nanosecond?

by Allison Goss 12. March 2015 12:01

Did you Know? API’s Coaxial Delay Lines offer delays of 1 nanosecond, operating at 70% the speed of light

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RF/Microwave & Microelectronics

Delay Lines Week: Did You Know... API's Delay Lines Help Prevent Car Accidents?

by Allison Goss 12. March 2015 09:34

Did You Know? API’s Delay Lines are used in collision avoidance systems. Collision avoidance systems and driver-assist technology uses radar to detect moving vehicles and stationary objects. If your vehicle has this type of technology, there may be a delay line integrated into the system to process the radar signal!

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RF/Microwave & Microelectronics

Delay Lines Week: Where Can You Find API's Delay Lines?

by Allison Goss 11. March 2015 09:20

Weather radar. Electronic warfare (EW) target generation. Clock synchronization. What do all of these systems have in common? API's delay lines can be found in all of them, plus many others.

Delay Lines APPLICATIONS API Technologies Where Can You Find API's Delay Lines? API's Delay Lines, featuring BAW (Bulk Acoustic Wave), SAW (Surface Acoustic Wave), Coaxial ­ High Frequency, LC (Lumped Constant), & Steel ­ Pulse Compression topologies, are used in a number of applications. Maritime Radar Doppler Processing Weather radars emit pulses which track the movement and location of objects like raindrops, hailstones, etc. Delay lines are used to control the timing of these pulses. On-board radar scanners provide bearing and distance of ships and land targets in the vicinity for collision avoidance and navigation at sea.EW Target Generation Communications Systems Clock Synchronization A radar target generator passes a radar signal through delay lines to a receiver to simulate a fixed target in time, which may be used to range calibrate the system. In many telecommunications networks, delay lines are used to synchronize information to set clock timing. Delay lines provide required delays to synchronize data for video or communication systems such as those used in TV broadcasting. micro.apitech.com/delay_lines

 Learn more about API's delay lines applications, request a quote, or contact us.

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Infographics | RF/Microwave & Microelectronics

Delay Lines Week Meet the Team: Bob Comstock, General Manager

by Jaymie Murray 10. March 2015 13:57

In his role as the General Manager of API's Auburn, NY facility, Bob Comstock works with several delay line topologies, including BAW, Dispersive Steel, Coaxial, and Lumped Constant (LC). In this Q & A, he discusses some of our delay lines, their applications, and what sets us apart from our competitors.   

Q: How long have you been here at API?

A: I’ve done a few long stints off and on over the past 30 years, so I would say that I’ve worked here for about 21 years total. During that time I’ve worked extensively with several of our delay lines topologies. In the early 80s, it was Dispersive Steel delay lines that were used to enhance radar signals for smaller targets. In the 90s, I worked with long dispersive delay lines that were also used in radars. From about 2002 until now I’ve been heavily involved with BAW (Bulk Acoustic Wave) delay lines in the 10 MHz – 120 MHz range with varying delays. These are primarily used for target generation, radar calibration, EW (Electronic Warfare), and digital memory delay. The BAW delay lines that calibrate radar and display systems are made out of quartz or glass that can be unheated or heated for increased stability.

Q: What other Delay Line products are made in the Auburn facility?

A: We also manufacture Lumped Constant (LC) delay lines that are used for video delay. They have short timers with delays of only a few nanoseconds to microseconds and feature discrete capacitors with digital inputs. 

Then there are our Coaxial delay lines which are made out of coaxial cables with a high frequency range and short delays of 250 nanoseconds down to 1 nanosecond, which is 70% the speed of light. These cables range from ¼ in long to 225 ft. long. With Coaxial delay lines the longer the cable, the longer the delay. 

Q: How do we add value for our customers?

A: We customize our delay line products about 99% of the time, so our customers almost always get a solution that is tailor-made for their specifications and needs. Our customers can also rest assured that these products are made to be highly reliable. Our Dispersive Steel delay lines are known to be used for 20 years without any issues, and they frequently do not need to be retuned until they have been in use for 30 years.  Our BAW delay lines provide a passive, stable delay source which can serve as reference for radar systems for many years, which is extremely important for radar calibration. 

We also offer a lower frequency Coaxial delay line box with switches that allow for trimming up to 10 radar channels. The customer can then control the trimming based on the delay that is needed. This is primarily used for multiple channels that need to be arranged in time, with each step having a 1.4 nanosecond change.  

Learn more about API's Delay Lines, request a quote, or contact us

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Meet the Team | RF/Microwave & Microelectronics

Delay Lines Week Meet the Team: Mike Schweyer, SAW Product Line Manager

by Jaymie Murray 10. March 2015 09:01

As the SAW (Surface Acoustic Wave) Product Line Manager at API's Marlborough, MA facility, Mike Schweyer works directly with customers to find the best SAW Delay Line solution to fit their needs. API offers a variety of SAW Delay Line bandwidths, frequencies, packaging, and substrates, which ensures that customers get a solution that meets their exact requirements.

Q: What is your title here at API and what is your background?

A: I’m the Product Line Manager for SAW products at API’s Marlborough, MA facility. I got my degree in electrical engineering from the University of Maine and I’ve been in this field for 15 years. During my career, I’ve worked mostly with different types of SAW (Surface Acoustic Wave) products, including SAW delay lines.

Q: How are delays created in the SAW delay lines?

A: We use three different substrates that have different wave velocities which produce different delays. We choose the substrate based on the end use. We also use aluminum transducers that convert an acoustic wave to a fixed velocity, and then we can adjust the delay based on how far apart we place the transducers. The further apart the transducers, the longer the delay. 

Q: Where can API’s delay lines be found and why are delay lines needed?

A: For example, the military uses our SAW delay lines for radar calibration and jamming. The delay lines allow the radar system to effectively process and synchronize signals that are traveling at the speed of light. Without the delays, the radar wouldn’t be able to interpret all of the signals it is receiving.  

Q: What makes our SAW delay lines unique to our customers?

A: There are a few reasons. First, we manufacture our SAW delay lines in a MIL-PRF-38534 Class H and Class K facility in Marlborough, MA. While this is a requirement to do business with military customers, we use the same equipment and design philosophies when we are working with our commercial customers, resulting in the same high quality, high reliability products.

We pride ourselves on being able to successfully deliver on even the most difficult technical specs. As an example, while the typical SAW delay line is around 13.3 mm x 6.5 mm, we created packages that are as small as 3 mm x 3 mm for customers that needed an extremely small footprint. 

API doesn’t just deal in extremely large volumes like a lot of our competitors do. None of our SAW delay lines come off the shelf, they are all either semi-standard or custom. Over the years, we have created over 3000 different designs, so we have the heritage and experience customers need. 

API also offers an integration team dedicated to creating a complete solution for customers. We can craft an entire sub-system using the other products in our RF & Microwave line. If a signal needs to travel a particularly long distance, we can add one of our amplifiers to the sub-system. That amplified signal can then be delayed based on customer requirements.

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Meet the Team | RF/Microwave & Microelectronics

Introducing Delay Lines Week

by Jaymie Murray 9. March 2015 09:36

API’s extensive catalogue of delay lines offer a range of semi-standard and customizable topologies that feature wide bandwidths and low insertion loss. Our BAW (Bulk Acoustic Wave), SAW (Surface Acoustic Wave), Lumped Constant, Steel Dispersive, and Coaxial - High Frequency delay lines are available in a variety of package sizes and interface options, ensuring that our customers will get the best solution for their individual needs. All this week, we will be exploring the many features and applications of our delay lines and what they can offer to customers that require both high performance as well as high reliability. 

Delay Lines API TECHNOLOGIES BAW Topologies SAW Low frequency Bulk Acoustic Wave (BAW) Delay Lines offer a wide range of semi-standard or custom delay solutions designed to meet unique specifications. Many interface options are offered including SMA (Female and Male), N-Type (Female), TNC (Female), Leaded and SMD. Packaging options include low cost, plastic encapsulated or hermetically welded. BAW delay lines are available in both connectorized or pin and surface mount. Frequency Range: 20MHz - 2000MHz Delay: 0.1µsec – 10µsec InsertionLoss: Starts at 3dB, increase withdelay and bandwidth Frequency Range: 10MHz - 120MHz Delay: 0.15µsec – 3,000µsec InsertionLoss: 6dB – 65dBSteel Dispersive Lumped Constant Coaxial Non-dispersive and dispersive SAW Delay Lines offer semi-standard or custom designs with various delay and bandwidth options. SAW Delay Lines are available in several packaging options such as ceramic leadless chip carriers, which provide small size and weight, and platform packages, which are suited for harsh applications. API Technologies has experience with delay lines on various substrates including quartz, lithium tantalate and lithium niobate. All SAW Delay Lines are hermetically sealed to ensure robust performance. Lumped Constant Delay Lines offer excellent frequency stability in semi-standard or custom designs to meet unique specifications. Active buffered, passive fixed and variable designs are available. Many interface options are offered including DIP, SIP Leaded and SMD. Packaging options include low cost, plastic encapsulated or hermetically welded. Pulse compression Dispersive Steel Delay Lines are offered in semi-standard or custom designs and available in many interface options including SMA (Female and Male), N-Type (Female), TNC (Female), Leaded and SMD. Our dispersive Steel delay lines can be ovenized for high stability center frequencies. Non- or hermetically welded packaging options are available. Frequency Range: DC- 6GHz Delay:1nsec -250nsec InsertionLoss:0.2dB-50dB Frequency Range: 5MHz - 65MHz Delay: 10µsec - 350µsec InsertionLoss: 20-45dB Frequency Range: DC - 150MHz Delay: 10nsec – 5000nsec InsertionLoss: 5% bandwidthHigh frequency Coaxial Delay Lines utilize semi-rigid cable, from small diameters, such as .041” up to diameters of .250”. API’s coaxial delay lines can be easily adjusted by changing the length of the cable and can be heated to improve temperature stability. Many interface options are offered including SMA (Female and Male), N-Type (Female), TNC (Female), Leaded and SMD. API offers a wide range of semi-standard and custom coaxial delay solutions designed to meet customer specifications for a wide range of applications. InsertionLoss:0.2dB-50dB Applications Signal Processing Circuits Radar Systems Electronic Warfare Clock Synchronization micro.apitech.com/delay_lines

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