As computers become more prevalent in our daily lives, being able to record an analog signal, whether it be someone’s voice or through a telegraph, and convert it to a digital format for editing, manipulation, and storage. In the world of digital signal processing, advanced technologies are needed to manipulate signals and change them from analog to digital. An RF downconverter is one such technology that allows a processor to convert digital signals.
For the uninitiated, digital signal processing can be extremely confusing. To put it in its most basic terms, a signal is simply a function that conveys some information. This can include audio or video, images, voice, text, geophysical coordinates, sonar and radar waves, and even musical tones. These different ‘signs’ often come in pairs or groups.
When this happens, a mixer is used to manipulate and convert those signals. When mixing two input signals, the output possibilities are the sum of the signals, the difference of the signals, and the two separate signals. Typically, the difference of the two signals, also known as the baseband signal, is the most useful in terms of transmission. A digital down converter or DDC is the device used to change the two input signals to a zero frequency difference signal.
It’s important to remember that all signals, even video signals, travel in waves similar to what you may have learned about in your high school trigonometry class. Do you remember sine and cosine? When two signals have different frequencies, a large amount of bandwidth is needed to transmit and receive the two waves of each signal.
Instead of transmitting two separate signal waves, a downconverter finds a pattern where these two waves meet at a fixed interval. The points in this interval where the waves meet are known as sampling points. These sample points are then used to create a completely new wave that describes your pattern. This new signal is the down-converted difference signal which is much easier to transmit and requires much less bandwidth and power.
For example, you might want to send a video message to your friend. This includes a signal for audio and a signal for video, both with very different frequencies. A downconverter takes these two signals, finds their difference pattern using an advanced calculation formula, and transmits the two signals into a new, more efficient signal. An RF converter makes sure that these two signals are converted so that they can be transmitted with maximum efficiency, speed, and fidelity.
While it may sound complicated, in truth, an RF type converter is actually a very simple circuit that can be built at home with minimal electronics knowledge or soldering experience. In fact, the device requires only three components that can be purchased at most electronics and parts stores. The converters are made up of a coaxial mixer, a low noise amplifier and a power regulator.
