Digital is abstract information . It is a meaning we choose to assign to physical values. This is why you cannot send a digital signal over the air as radio waves. It must be converted first into something that exists outside of abstraction, like an analog signal which represents the information to be transmitted.
In analog communication system, the signal travels over a longer distance it amplitude reduces due to attenuation and received signals becomes distorted. In digital communication systems, repeaters are introduced between the source and destination.
Video modulation is a strategy of transmitting video signal in the field of radio modulation and television technology. Then, the carrier will “carry” the information in the form of radio frequency (RF) signal . When carrier reaches its destination, the video signal is extracted from the carrier by decoding.
Which is better , analog or digital ? An analog watch might be much more accurate than a digital one if it uses a high-precision movement to measure passing time. Generally, the most expensive watches in the world are analog ones, though the world’s most accurate atomic clocks show time with digital displays.
Analog signals are composed of continuous waves that can have any values for frequency and amplitude. Digital signals are a more reliable form of transmitting information because an error in the amplitude or frequency value would have to be very large in order to cause a jump to a different value.
The required bandwidth is increased due to digital technology. System Complexity is increased. In order to convert the analog signal to digital prior to transmission and then from digital to analog receiver, we need to use the additional encoder and decoder circuit.
Over such small distances , digital data may be transmitted as direct, two-level electrical signals over simple copper conductors. This results from the electrical distortion of signals traveling through long conductors, and from noise added to the signal as it propagates through a transmission medium.
The effect of distortion, noise, and interference is much less in digital signals as they are less affected. Digital circuits are more reliable. Digital circuits are easy to design and cheaper than analog circuits. The hardware implementation in digital circuits, is more flexible than analog .
Types of Video Signals: 1) Component Signal: color reproduction since there is no crosstalk between the three channels. Component video requires more. bandwidth and good synchronization of the three components. 2) Composite Signal: Color (chrominance) and intensity (luminance) signals are mixed into a single carrier wave. 3) S-Video Signal:
The rays reflected from the latter impinge on a photoelectric converter, thus creating video signals. The highest frequency in the video-signal spectrum is a function of the rate at which the image is scanned and varies over a wide range (80 Hz to 6 kHz ). The video signal in radar is in the form of pulses.
Sync, video , chroma, closed captioning. Composite Video is of a specific voltage , and requires a specific working impedance for its distribution between video instruments. The spec is for a signal that is one volt peak to peak, terminated into 75 ohms.
The term analog signal usually refers to electrical signals; however, mechanical, pneumatic, hydraulic, and other systems may also convey or be considered analog signals.
The most important reason to make the switch to a digital signal is because it will free up valuable portions of the broadcast spectrum, which can then be used for other purposes, such as advanced wireless services and for public and safety services.
As long as nothing corrupts a digital file, it will stay the same no matter how much time has passed or how many copies engineers make. Today, technology in the audio recording industry is so advanced that many audio engineers will tell you there’s no detectable difference between analog and digital recordings.