The Importance of Analog Engineering Skills to the Electronics Industry
We hear phrases like “the digital economy “and “digital transformation” so often that they have almost become clichés. Industry’s focus on digital technology means that many may forget that the real world is not digital, but analog in nature.
Figure 1 Analog and Digital Thermometers
The misperception that perhaps ‘analog’ technology is outdated and no longer relevant is having serious repercussions for the electronics industry, resulting in many undergraduate and graduate engineers opting to align their studies and research with digital electronics only.
This is creating a lack of understanding and practical experience of analog design and application skills among electronics engineers. Made worse by the fact that many young engineers think analog circuit design is poorly defined, requires regular use of difficult mathematical calculations, and lacks the sophisticated software tools available to digital engineers. Unless this trend is quickly reversed, the electronics industry will soon reach a point where there are not enough engineers with analog experience for it to deliver innovation in line with consumer expectations.
With this four-part blog series, we are aiming to redress the balance of knowledge and understanding of analog design. Over the coming weeks, we will review the basics of analog circuit design and the tools that are available to engineers, enabling them to design with confidence. We will demonstrate that analog circuit design has evolved and now has a highly structured methodology. We’ll explore some of the advanced hardware and software tools available that are helping to reduce the need for many complex manual calculations. And hopefully achieve our goal of encouraging more young engineers to look at analog circuit design as a highly valued and rewarding skill, and one that will further enhance their career development options.
What are ‘Analog’ and ‘Digital’?
Analog refers to signals or information represented by a continuously variable physical quantity. Examples of analog quantities include voltage, light, heat, pressure and sound. In contrast, the digital representation of a quantity can only ever be one of a pre-defined number of pre-set (or discrete) values. The difference between analog and digital can be illustrated using the following simple examples:
- Turning the light in a room on fully or off (digital) versus using a variable dimmer switch to set the lighting to a desired level of illumination (analog).
- Using a thermostat that turns a heater fully on and fully off when the temperature in a room exceeds or falls below a pre-set value (digital) versus a thermostat that continuously adjusts the operation of the heater to keep the room temperature at a pre-set temperature (analog).
- An audio system with pre-set volume controls (digital) versus one with rotary control that allows the volume to be set to any desired level (analog)
The reason why analog quantities are converted into a digital form is that they can then be quickly processed by digital circuits. However, this does not mean digital signals are always the most accurate. Using the example of a thermometer, unlike its analog counterpart, a digital thermometer only measures temperature at periodic intervals – a process referred to as sampling. Secondly, it can only display that measurement using one of its pre-set values – a process called quantization.
Therefore, for the display on a digital thermometer (Figure 1) to update in response to a change in temperature, it must first perform its measurement (which may happen after the temperature change has already occurred), and secondly, the measured change must be bigger than the smallest pre-set value that it can recognize. Admittedly, the latest digital instruments are now designed to make many high-speed measurements and to recognize very small changes (due to having many discrete values). And while they can never be quite as accurate as their analog counterparts in pure measurement terms, their performance is usually sufficient for the application that they serve.
Sensors
A sensor (or transducer) is used to detect and convert one form of energy into another, for example capturing temperature, light, or sound, and converting it into electrical energy, usually in the form of an analog voltage signal. Sensors commonly used to detect temperature include thermocouples and resistance temperature detectors (RTD) while photodiodes are used to detect light, and microphones for sound.
Conclusion
Ultimately, most sensors operate on analog principles, and the electrical output signals that they produce are usually very small (millivolts or less). This means that their signal must be conditioned to remove noise and increase amplitude or level, before converting it into the digital form required by the downstream control system. The sensor and the circuitry used to do this conditioning are called the analog signal chain (amplifiers, filters, and data converters), which we will explore further in our next article.
Stay tuned for the next blog in the series: Signal chain basics.
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