Slight variations in the peak deviation may occur in the presence of other subcarriers or because of local regulations. In addition, for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver. As with monaural transmission, it is normal practice to apply pre-emphasis to the left and right channels before encoding and to apply de-emphasis at the receiver after decoding. A handful of radio stations around the Country are broadcasting stereo in this way.
AM, FM Waves and Sound To understand some of the concepts we introduced in the last module, as well as some of the strange things that happen to broadcast signals, we need to take a look at how radio works.
First, let's look at the AM radio band group of frequencies. AM stands for amplitude modulation, which will be explained later. AM radio ranges from to kHz kilohertz, or thousands of cycles per-second of electromagnetic energy.
These are the numbers you see on your AM radio dial. Note in the tan area at the left of the illustration below that AM radio waves are of a lower frequency than either FM radio or TV waves. Thus, as we will see, after being transmitted, they will behave differently.
Stations can theoretically be placed every 10KHz, along the AM band. This means that there are a total of different channels available for AM radio stations. If it all stopped there, things would be rather simple; but, unfortunately, other factors come into play.
First, you can't put stations on the same frequency that are too close together in a geographic area. They will interfere with each other. And for the same reason you can't have two stations close together in frequency close to each other on the radio dial in the same area.
So these are the first things that limit the number of radio stations in an area. The good news is that since the signals of stations tend to be limited in their range, you can use some of the frequencies many times — as long as the stations are far enough apart geographically.
This is why the United States can have nearly 5, AM radio stations on only different frequencies. How far an AM station's signal travels depends on such things as the station's frequency channelthe power of the transmitter in watts, the nature of the transmitting antenna, how conductive the soil is around the antenna damp soil is good; sand and rocks aren'tand, a thing called ionospheric refraction.
The ionosphere see illustration below is a layer of heavily charged ion molecules above the earth's atmosphere. Are you still there? Okay, let's go on. Ionospheric refraction is a big issue, because AM radio waves can end up hundreds and even thousands of miles away from where they started, and in the process interfere with all other stations on the same frequency.
But, as we'll see in a later module on international shortwave, ionospheric refraction can be good, because it makes possible long-distance communication.
Here's how that works.edit Tell us where you are located and we can tell you what's available. The many faces of Christina Bianco light up the Gaslight Cabaret Festival. 12 band radio includes AM, FM, TV and SW1-SW9. Naxa Electronics 7IN BT DVD BMBOX/TV. by Naxa Electronics.
$ $ 99 $ FREE Shipping on eligible orders. Only 2 left in stock - order soon. Product Features over-the-air HD TV stations Plays CDs, MP3s or AM/FM radio broadcasts. AM, FM Waves and Sound. To understand some of the concepts we introduced in the last module, as well as some of the strange things that happen to broadcast signals, we need to take a look at how radio works..
First, let's look at the AM radio band (group of frequencies). AM stands for amplitude modulation, which will be explained later.. AM radio ranges from to kHz (kilohertz, or.
Portable TV Band AM/FM Radios Whether you are getting ready for a day at the beach or a long camping trip, a portable TV band AM/FM radio can be a useful technological addition.
A portable unit such as a compact transistor radio or digital radio is light enough to throw in a backpack, but it is still powerful enough for tuning in FM music and. According to the government's most comprehensive assessment to date, climate change has already damaged American infrastructure and cost both money and lives.