Analyzing the technical requirements for high-end imaging and portable diagnostic systems

The systems mentioned above require accurate measurements, precise data handling and highly complex digital processing, especially when the output is in the form of images or videos. These technologies have also been transferred to other fields, such as military/aerospace and transportation.

Advances in silicon design mean that the sophistication of key semiconductors has increased dramatically, especially DSPs , FPGAs , microcontrollers, and high-performance analog devices. Similarly, imaging technology is being integrated into more and more traditional semiconductor areas as touch screens and more sophisticated human-machine interfaces are added to these applications.

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Many devices and medical systems use video and image outputs to facilitate diagnosis and therefore make extensive use of signal processing techniques.

Radiography, tomography, ultrasound and fluoroscopy are just a few examples of these applications.

A wide range of technologies are required to implement these functions, and the trade-offs between performance and power consumption still exist (even if they are becoming less and less as technology advances), which focuses on the right technologies to use. Generally speaking, high-end processing refers to programmable logic solutions and DSPs, while the low-end area, where power consumption is a key factor, refers to microcontrollers. Of course, the differences between these technologies are shrinking at a very fast rate, and programmable solutions can now be found in handheld devices.

Programmable logic such as FPGAs and CPLDs now incorporate complete microcontrollers and other specialized soft IP blocks with multiple parallel routing channels responsible for executing the entire algorithm within a single clock cycle. Note that such systems contain a long pipeline, meaning that the algorithm can be processed within a single clock cycle, but there is a delay from the time the input is obtained to the time it affects the output.

Since these algorithms are implemented digitally, performance is a concern. The faster the processing algorithm, the greater the flexibility and value of the product. However, high speed may mean more power consumption and shorter battery life.

FPGAs offer many advantages over traditional components, especially for low- and medium-volume devices.

The programmable nature of the chip can save up to about 30% of development time, and it can be upgraded later. Using FPGAs can also reduce the consumption of expensive electronic components. FPGAs have become more common due to the complexity of chip design and the increasing sophistication of silicon processing technology.

There are many choices for processor cores in other applications. In industrial applications where RISC is more common today, the ARM7 core has been widely used by microcontroller manufacturers such as NXP, Atmel, ST and ADI, while the ARM9 is becoming increasingly popular. i.MX application processors such as Freescale are based on the ARM9 processor with a highly integrated LCD controller and are gaining more and more attention in the imaging field.

For imaging applications, MIPS is also working to move into this market from its dominance in the consumer/connectivity space, and has begun to enter the 32-bit processor arena with the MIPS32 core in partnership with Microchip. Designers who prefer CISC architectures can find examples from companies such as Intel and Renesas.

For real-time imaging, DSP still occupies an advantageous position despite the strong threat of FPGA. New platforms have emerged that include MCU and DSP on the same silicon chip, which can perform image processing and general processing. TI's latest Da Vinci processor is designed for multimedia applications. Freescale and ADI also provide very powerful solutions.

High-performance analog components

Sensing is a large area in both instrumentation and medical applications. For example, the emergence of CapSense from Cypress Semiconductor and CapTouch from ADI has provided new possibilities for touch screen technology to realize innovative HMI solutions.

The demands on analog components are very similar in medical and instrumentation applications, as well as in other industries such as ATE and military/aerospace. All of these areas require amplifiers with low noise, low distortion, high speed and low power consumption ; digitally programmable amplifiers and wide bit conversion (up to 24 bits).

Human contact

Outputs from instruments and medical devices are often required. This means that the conversion and presentation of data must be clear and, for medical electronic devices that must interact with the human body, such as a defibrillator, the output must be accurate.

ESD plays a big role here; it is a particularly difficult parameter to predict due to inconsistencies in air temperature. A recent article from Linear Technology suggests that walking on a wool blanket with leather shoes in dry winter weather can generate 10KV to 15KV, while the voltage generated in humid summer weather is less than 2KV. This static electricity accumulation on the human body is called triboelectricity, and the human body can accumulate 35KV in some cases, so it is an issue that design engineers must consider. For this reason, various common tests have been designed to reduce damage to the equipment in use and provide continuous operation capabilities. One of the most common tests in the United States uses a mannequin to simulate the ESD discharge waveform generated by human contact with an electronic device, based on the more tolerant Japanese mechanical model. Typically, RS232 transceivers can withstand voltages of more than ±10KV when tested with a mannequin. The more commonly used IEC801 test is ±7.5KV. Linear Technology's LTC2850 is an example of this test.

FCC and other international regulations are used to reduce emissions from electronic devices. EMI (electromagnetic interference) regulations reduce interference between electronic devices and raise health and safety issues.

Designers can control the radiated emissions through shielding of radiating circuits and cabling systems, bypassing, board layout, and many other techniques. Maxim/Dallas has several oscillator and frequency generation products that incorporate low EMI designs. A recently developed technique called "diverging," or dithering, the center frequency of clocks used in computers and power supplies spreads the radiated energy over a band of frequencies rather than at a single frequency.

Either way, you need power.

Power can be provided in several ways, from batteries to high-power AC outlets. Hearing aids, pacemakers, and handheld devices all maximize battery life. Magnetic resonance imaging (MRI) and X-ray machines require high voltages for short periods of time to drive RF transmitters . Some equipment has bed systems with servo motors to facilitate patient movement and positioning.

Power supply wiring is equally important not only for circuit power management , but also for the surrounding components - resistors, inductors, capacitors, relays and connectors. The following article examines the advantages and disadvantages of some products in this range, as well as regulatory issues.

What will be your future job?

It is clear that the next 10 years will be a decade of growth for the healthcare market, including instruments, imaging and medical monitoring. There will be a large number of technological advances that will also have an impact on the development of auxiliary devices in core instruments, automation and industrial applications. We focus on these technology developments and ensure that the latest products are introduced to the market as quickly as possible to take advantage of these existing advanced technologies.