Detailed integration of transceivers to bring SWaP solutions

The new generation of aerospace and defense platforms will present new challenges, and the solutions they need cannot be achieved by optimizing the devices individually. Integrating more software control and cognitive capabilities into the radio requires a more RF design that is more flexible in terms of frequency and bandwidth. In order to achieve this goal, it is necessary to cancel the static filter and replace it with a tunable filter. Similarly, the concept of a common platform will help reduce development time, reduce production costs, and improve interoperability between systems. Common platforms require RF systems to help applications that traditionally use different architectures to maximize their performance. Finally, the future platform will push the size and power requirements to new extremes.

Handheld single-player radios continue to grow in functionality, complexity, and battery efficiency. Small unmanned aerial vehicles do not have the power generation capacity of large aircraft, and every milliwatt of electrical energy consumed by the RF system is directly converted into the weight of the payload battery, thereby shortening the flight time. To overcome these challenges and create a new generation of solutions, a new radio architecture is needed.

Superheterodyne architecture and diminishing returns

Since its introduction, the superheterodyne architecture has been the backbone of the aerospace and defense system radio design. Whether it's a single-player radio, unmanned aerial vehicle (UAV) data link, or a signal intelligence (SIGINT) receiver, single or dual-mixer superheterodyne architectures are a common choice. The advantages of this design are obvious: reasonable frequency planning can achieve ultra-low spurious emissions, channel bandwidth and selectivity can be set by an intermediate frequency (IF) filter, and the gain distribution at each stage allows for noise figure and linearity. Weigh the balance.

Figure 1. Basic superheterodyne architecture

In more than 100 years of operation, the performance of superheterodyne in the entire signal chain has been significantly improved. Microwave and RF devices improve performance while reducing power consumption. The ADC and DAC increase the sample rate, linearity, and effective number of bits (ENOB). The processing power of FPGAs and DSPs follows Moore's Law and has improved over time, creating conditions for more efficient algorithms, digital correction, and further integration. The packaging technology reduces the density of the device pins and improves the heat dissipation of the package.

However, these device-specific improvements have begun to move toward a point of diminishing returns. Although the trend in RF components is to reduce size, weight, and power consumption (SWaP)—the physical size of high-performance filters is still large, and custom designs typically increase the overall cost of the system. In addition, the IF filter determines the analog channel bandwidth of the platform, making it difficult to construct a common platform design that can be reused in a wide range of systems. For packaging technology, most production lines do not use pin pitches below 0.65 mm or 0.8 mm, which means that complex devices with multiple I/O requirements can be miniaturized in physical size.

Zero intermediate frequency architecture

An alternative to the superheterodyne architecture is the Zero Intermediate Frequency (ZIF) architecture, which has emerged as a potential solution in recent years. The zero-IF receiver uses a single-frequency mixing stage with its local oscillator (LO) set directly to the target band and down-converts the received signal to the baseband in the phase (I) and quadrature (Q) signals. This architecture can alleviate the rigorous filtering requirements of the superheterodyne architecture because all analog filtering processes occur at the baseband. In the baseband, the filter design is much simpler and less expensive than a custom RF/IF filter. some. As a result, the ADC and DAC act on the I/Q data in the baseband, so the sampling rate relative to the conversion bandwidth can be reduced, thereby significantly reducing the power consumption level. From a number of design perspectives, zero-IF transceivers can significantly reduce SWaP by reducing the complexity of the analog front end and reducing the number of components.

Figure 2. Zero IF architecture

However, some flaws in this system architecture need to be addressed. The method of directly converting the frequency to baseband introduces carrier leakage and image frequency. Mathematically, the imaginary parts of the I and Q signals cancel each other out due to their orthogonality (Figure 3). Affected by real factors (such as process variations, temperature differences in the signal chain), it is impossible to maintain a perfect 90° phase shift between the I signal and the Q signal, resulting in a reduction in image rejection performance. In addition, imperfect LO isolation in the mixing stage can introduce carrier leakage. If not corrected, mirroring and carrier leakage issues can cause receiver sensitivity to drop, causing unwanted emission spectrum emissions.

Figure 3. Zero IF image cancellation

Historically, the I/Q imbalance problem has limited the scope of the zero-IF architecture. There are two reasons for this: First, the zero-IF architecture uses a discrete implementation, which results in mismatch issues in monolithic devices and printed circuit boards (PCBs). Second, monolithic devices may come from different production batches, and it is extremely difficult to achieve accurate matching due to process variations. In addition, the discrete implementation also physically separates the processor from the RF components, making it difficult to implement orthogonal correction algorithms across frequency, temperature, and bandwidth components.

Integrated transceiver brings SWaP solution

Integrating a zero-IF architecture into a single-chip transceiver provides a way for next-generation systems. By placing the analog and RF signal chains on the same piece of silicon, the effects of process variations can be minimized. In addition, the DSP block can be integrated into the transceiver, thereby eliminating the boundaries between the orthogonal calibration algorithm and the signal chain. This approach not only improves SWaP performance as never before, but also outperforms the superheterodyne architecture in performance specifications.

Figure 4. Functional Block Diagram for the AD9361 and AD9371

Currently, ADI has two transceivers for the aerospace and defense market. They are the AD9361 and AD9371. These devices integrate a complete RF, analog and digital signal chain into a single CMOS device. The integrated digital processing module can run quadrature and carrier leakage correction algorithms in real time, independent of any process, frequency and temperature differences. The AD9361 is targeted at applications that require medium performance specifications and ultra-low power consumption, such as unmanned aerial vehicle data links, handheld and single-person communication systems, and small SIGINT. The AD9371 is optimized for applications that require ultra-high performance specifications and medium power consumption. In addition, the device integrates an A RM® microprocessor for precision calibration control, an observation receiver for power amplifier (PA) linearization, and a sniffing receiver for detection of blanks space. This opens up new design potential for many different applications. Communication platforms that use wideband waveforms or occupy non-contiguous spectrum can now be implemented in much smaller packages. In locations where the RF spectrum is highly congested, the high dynamic range and wide bandwidth create conditions for SIGINT and phased array radar operations.

A new generation is in the moment

With 100 years of experience in device optimization, the Superheterodyne architecture enables ever-increasing performance on platforms that are shrinking in size and decreasing power consumption. With the advent of physical limitations, these improvements have begun to slow down. The new generation of aerospace and defense platforms will require a new approach to RF design. In this type of approach, several square inches of existing platforms will be integrated into a single device; the boundaries between software and hardware are blurred, enabling current levels of optimization and integration; reduced SWaP no longer means The performance is declining.

Now, with the combination of the AD9361 and AD9371, aerospace and defense designers have the ability to build systems that were not possible a few years ago. Both devices have many things in common—tunable filter angles, wideband LO generation, diversity capabilities, calibration algorithms, and more. But there are also key differences, and each device is optimized for different applications. The AD9361 focuses on a single-carrier platform where SWaP is the primary driving force. The AD9371 focuses on broadband, non-continuous platforms where performance specifications are more difficult to implement. These two transceivers will be key enablers in the next generation aerospace and defense signal chain.

Swivel Joints

Swivel Joints of various type including Swivel Joint,Swivels,Fixed Joint,U Joint,anti-bending Joint,Joint Connectors,Joint Tube Connector,Pulling Socks,Mesh Sock Connectors,etc,which is specially used for connect conductor or OPGW cables in power line project,etc.It is made of high strength steel or Alu alloy with small volume,light weight,no-damage to conductors.By high quality Alum or steel material and good design,this kind of Connectors & Swivel Joints can be durable and long service life.we are a professional Chinese exporter of Connectors & Swivel Joints and we are looking forward to your cooperation.

Yangzhou Qianyuan Electric Equipment Manufacturing & Trade Co. Ltd is specialized in manufacturing and trade of electric power line transmission tools. Our main products are Anti-twisting Steel Wire Rope,Stringing Pulley,Hydraulic Crimping Compressors,Engine Powered Winch,Motorised Winch,Wire Grip,Gin Pole,Cable Stand,Mesh Sock Grips,Cable Conveyor,Lever Chain Hoists and so on,which are mainly supplied to power companies,railroad companies and other industry fields.

All our products are certified by China National Institute.
To assure the quality, we will do 100% inspection for raw material, production procedure, packing before shipment,
so we do have the confidence to supply customers with high-quality and high-efficiency products.
"Customer satisfaction" is our marketing purposes,so we have extensive experience in professional sales force,and strongly good pre-sale, after-sale service to clients. We can completely meet with customers' requirements and cooperate with each other perfectly to win the market.Sincerely welcome customers and friends throughout the world to our company,We strive hard to provide customer with high quality products and best service.

swivel joints, wire rope swivels, u joint, fixed joint, d shackle

Yangzhou Qianyuan Electric Equipment Manufacturing & Trade Co.Ltd , https://www.qypowerline.com