The term “analog” derives from the Greek word ανάλογος (analogos) meaning “proportional.” By nature, an analog signal shares a proportional relationship among the signal, the voltage or current that sends it, and the medium through which it travels.
Analog, when duplicated or passed through other media toward its end destination, picks up outside “noise” or distortions; in a sense the medium becomes a part of the message.
Analog signals are measured responses to physical phenomena, such as sound, light, temperature, position, or pressure. (Think of a singer passing air across her vocal chords. As she runs out of air, either the signal dies or its tone is changed. Her sound is an analog.)
This physical variable makes the message an altered copy; thus, it is an “analog” of the original sound.
Video analog signals are, likewise, altered or distorted.
The development of digital signals in the 1970’s was an attempt to standardize the signal and reduce the variable of the “noise” picked up by analog signals. After some failed attempts, the experiment was successful, most notably by Intel, AMI and Texas Instruments. As time move forward, so did refinements in this process of converting analog signals into digital signals in the fields of audio and video.
What works for music and film in Hollywood also works for surveillance and safety in business locations. Digital is here to stay. In fact, it continues to get better.
High Definition, or HD, is a digital signal. HD-SDI, or High Definition-Serial Digital Interface, is straight line connection among devices capable of sending and receiving high-definition audio and video signals, which can be illustrated as:
– – – – – – – – -> versus —–>——->——>
(The signal on the left is HD; on the right is HD-SDI)
HD-SDI is cleaner and steadier, providing better clarity or resolution. The implication of the need for a clearer picture on surveillance videos and audio is obvious, but there are other benefits.
HD-SDI is an uncompressed transmission and display of digital HD signals via a serial (straight-line connections) (analog) interface. In plain words, video signals (images) can be sent and displayed in high resolution and in real time, allowing for:
For 20 years, Ortel Technologies has prepared its clients for the constant-change environment that is the world of surveillance cameras, monitors, converters and installation of the infrastructures (cabling) required to lead their respective fields and industries. As well, we have provided leading-edge Internet connection, service and support.