Month: March 2018

Analog : Data represented by continuously variable physical quantities, i.e. moving clock hands.

Digital: Data composed of bytes of information sampled at regular intervals.

Data acquisition for life science research and education has come a long way since the heyday of chart recorders and oscilloscopes. Chart recorders, while accurately rendering body signals using an ink stylus on long rolls of paper, lack the flexibility for closely analyzing or interacting with data. Oscilloscopes also pose similar limitations. The field of physiology study received a major assist with the advent of A/D (A-to-D) converters, which include industry-leading BIOPAC MP160, MP36/36R, or Smart Center Systems.
So what is an A/D converter? A/D converters are devices for converting analog signals to a digital format.

This principle can be applied to any type of analog information, such as recorded music or video, and lends itself especially well to conversion of physiological signals. The incoming analog signal (such as an ECG heartbeat) is “digitized,” which allows the signal to be accurately displayed on a computer monitor. During this process, the analog signal is “sliced” into samples per second (or Hz) by the A/D converter. The speed at which the signal slices are acquired is referred to as the sampling rate.

A good illustration of how a sampling rate works is to liken it to a dot-to-dot drawing, each dot appearing at regular intervals and tracing the amplitude and time outline of the incoming analog signal. The higher the sampling rate, the higher the concentration of dots, and the higher the resolution (quality) of the signal. The combined dots, or bytes, of digitized information are displayed onscreen as seamlessly precise waveforms that can be started, stopped, magnified, reduced, edited, autoscaled, transformed, or run through powerful automated analysis routines using BIOPAC AcqKnowledge Research Software.

A good acquisition sampling rate for most physiological data is 2000 samples/second, although certain body signals (such as lung volume measurements) require only 20 samples/second, while auditory studies benefit from a sampling rate as high as 20,000 samples/sec. The BIOPAC MP160 16-Channel Data Acquisition Unit supports sampling rates ranging from 0.1 samples/second to 200,000 samples/second. Try doing that with an analog chart recorder!

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BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

Data acquisition hardware and software packages have undergone rapid progress over the past several years. Cumbersome systems difficult to set up and operate have been superseded by compact modular arrays offering unprecedented convenience, power, and functionality. Researchers and educators in the field of data collection have never had it so good. One of the most oft-asked questions from current prospective end-users is which type of system will best serve my needs?

Wired systems have long been the bedrock of labs around the world. Components fit on a desk and connect to a laptop or desktop computer. The data acquisition unit (such as BIOPAC’s MP160) is combined with a scalable array of modular amplifiers, or in the case of BIOPAC’s MP36 or MP45, powerful functionality is built into an even more compact package. Wired systems generally offer a wider range of features, such as stimulation, MRI signals, gas analysis, laser Doppler flowmetry, pulse oximetry, variable rate sampling up to 400 kHz, more channels (including digital and calculation channels), and online signal averaging. Access to third-party hardware and special licensed features are more readily supported. In wired systems, the subject is tethered to the equipment via cabled transducers and/or electrodes, so if mobility isn’t an overriding concern, a wired system will prove to be a robust platform offering the fullest range of available data collection and analysis tools.

Despite the enhanced functionality offered by wired systems, many researchers and educators have embraced lightweight wireless systems (such as BIOPAC’s BioNomadix, BioNomadix Smart Center or BioNomadix Logger). Wireless systems offer the flexibility of allowing untethered subjects to roam freely, and are excellent for exercise studies or other protocols requiring unrestricted movement. All major physiological signals are supported, and data quality is equal to that of wired systems. Although sampling rates are limited to 2 kHz, this is generally more than sufficient for most physiological studies. The advantage of a wireless system is apparent when fast, accurate results from single or multiple ambulatory subjects are of paramount importance. The BioNomadix Logger even enables subjects to conduct lengthy protocols virtually unlimited distances from the lab, after which the data is downloaded to the computer, enabling researchers to analyze accurate physiological data acquired over time and distance. Certain advanced functionalities available in wired systems aren’t supported in wireless systems, so your lab’s necessity for these must also be carefully considered.

The bottom line is, if your lab requires the full range of available biometric signals in conjunction with advanced functionalities—and subject mobility is not a factor—wired systems are recommended. If compactness, mobility, portability, and access to all major life science signals are deciding factors, then your lab would be well-served by a wireless system.
When your experiment needs flexibility, portability or fast and easy setup, then the wireless Smart Center is the right choice.

Learn about BIOPAC’s newest wireless recording system in “Get Better Physiology Data—BioNomadix Smart Center.”

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BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.