Radio Receivers Are Evolving All The TimeOne of the most crucial components in radio technology is the receiver, and without one, many applications are obsolete. A radio receiver functions as the very important component that converts the radio signal into sound. Receivers go through the process of obtaining the signal from the antenna and then converting this signal into the corresponding pictures, sound, navigational position information, and whatever other information is being transferred through that signal. In most instances, when the term "radio receiver" is used, it is referring to the type of radio receivers that only have sound. There are many various types of radio receivers, including crystal radio receivers, am radio receivers, and fm radio receivers. For radio receivers to perform at their best, it is important to have all of their elements at peak performance level. To do so, specifications must be checked for things such as dynamic range, filter shape factor, sensitivity (SINAD, signal to noise ratio, and noise figure), and selectivity. Some of the most common circuits and techniques included in radio receiver technology are: Demodulation, DSP, Frequency Synthesizers, PLL, Filters, and SDR. Each of these will be discussed briefly.
Demodulation can be done in a few different ways. Receivers need a baseband signal, and to obtain this signal, it is necessary to remove the modulation from the analog signal by using the process of demodulation. DSP, or Digital Signal Processing, is a widely used technology for situations where it is necessary for signals to be processed. As the name dictates, Digital Signal Processing is the method of processing signals in a digital format. Frequency Synthesizers are one of the most common components of the radio receiver. It is used in a plethora of other electronic devices as well, such as walkie-talkies, CBs, and mobile and radio telephones. The importance of the frequency synthesizer is that it generates ranges of frequencies from a timebase or oscillator. Most of the frequency synthesizers that are used in radio receivers make use of the PLL circuitry. PLL, or Phase locked loops, is a very common and flexible type of circuitry used for synthesizers, Fm demodulators, etc. It is not only found in most radio receivers, but is found in other pieces of electronic equipment as well. Filters are another crucial piece of the radio receiver puzzle. There are many different types of filters that can be used, including mechanical, crystal, LC, and ceramic. Each of these filters plays an important role in providing selectivity. Lastly, the SDR, or Software defined radio. There are many benefits to having SDR. This is a newer technology, and many are striving to move toward using SDR instead of other methods. Perhaps the largest benefit of using SDR is that most of the data is housed within the software, so that upgrades or other types of technical changes could be made merely with a software update instead of having to do hardware updating. Unfortunately, there are still some limitations, but hopes are that the kinks will continued to be worked out in years to come. In conclusion, radio receivers are an important part of our electronic world. There are many devices that would not be able to work properly without them. As with many other pieces of electronic equipment, the radio receiver is evolving and changing with time, and will continue to play an important role in our technological world. |
