Analog (Technology) Is Here to Stay
Security Sales & Integration’s Tech Talk columnist Bob Dolph sings praises to analog’s unwavering tech influence in the security industry.
We live in an exciting technological age. The introduction of computers has brought us into what is often referred to as the “digital world.” Much of this world is becoming second nature to today’s novice technicians as it has become the only technical world they have known since a very early age. But what are the skills they will need to install and service today’s systems?
Let’s take a moment and step back in my time machine. The year is 1958 and there is a music revolution going on called rock ‘n’ roll. A popular music group called Danny & The Juniors had just released their second hit 45-rpm record – “Rock and Roll Is Here to Stay” – and with it created a rock ‘n’ roll anthem that stands the test of time. Just as rock music was emerging, this was also an era of emerging technologies in the security industry such as ultrasonic and microwave motion sensors, color video cameras, and recorded message alarms over phone lines.
Continued Influence in a Digital World
The word analog describes a device or system that represents changing values as continuously variable physical quantities. This can be anything that deals with our senses of sight, sound and light. In general, humans experience the world in an analogical manor. So you can see this is not something that is going away anytime soon.
In keeping with this month’s analog theme I have selected a recently released and already popular sound pressure level (SPL) meter called the dBchecker DB02 from SDi.
In the past it was somewhat expensive to find an SPL meter that met ANSI S1.4a requirements as listed in NFPA 72 126.96.36.199 (15), but the dBchecker can be found for less than $100. It tests 40dB to 130dB over four ranges, according to the company, with readings on a four-digit LCD display.
Low-voltage electrical systems in general are analog systems, though the data that flow through them may be digital. Technicians must understand the fundamentals of power, voltage, current and resistance. They must understand relationships such as Ohm’s and Kirchoff’s circuit laws. This, along with troubleshooting skills when using a digital multimeter (DMM), is critical. Plus, calculating these very small (think milli- and micro-) or very large (think Mega- and Giga-) numbers containing many zeros that you will come across can easily lead to mistakes. That is why methods such as scientific notation and logarithms were created.
Help Yourself by Understanding Some Basics
Fire alarm systems require a technician to understand the measurement of sound. How loud (in decibels or dB) is the smoke alarm? Does it meet NFPA 72‘s “75dBA to pillow” requirements? Do you understand sound pressure levels (SPLs) to decrease 6dB with a doubling of distance? Basic dB calculation rules are pretty simple; every time you double or halve the power level, you add or subtract 3dB to the power level.
Those working on commercial sound systems must know all of the above but may also deal with what is called a 100/70/25V constant voltage audio system. The most popular being the 70.7V system, in which loudspeakers with multitap transformers are used. HVAC system monitoring controls can sometimes use what is called a 4-20ma current loop. This analog technology allows temperature sensors to transmit information via basic cabling 1,000 feet or more.
The simple physical fact of many systems, whether they be electrical category cable or fiber-optic networks, or popular radio frequency (RF) antenna systems, is that all will experience the common problems of background noise (signal-to-noise ratio) and connectivity signal attenuation. These are analog conditions usually measured in those aforementioned logarithmic units called decibels – another measuring stick that analog is here to stay.
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