Frequency components in a singnal.

Peon666

From a book:

"The waveform is distorted because of different amounts of attenuation and phase shift suffered by different frequency components of the signal"

Question:

If there are different frequency components in a single, how do the ratio channels operate on a single frequency. A channel, for example, operates on the frequency 101. How can this happen when the signal contains components of differing frequencies?

Thanks.

ShaneXavier

Any signal can be broken down into an infinite number of simple sinusoid components. Fourier is mind blowing.

http://mathworld.wolfram.com/FourierSeries.html

berkeman

The channel has some bandwidth, so that gives rise to different frequency components being in even a narrow-band signal.

The bandwidth of each US FM broadcast radio station is 200kHz, in the band from 87.8 MHz to 108.0 MHz.

http://en.wikipedia.org/wiki/FM_broadcasting

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Peon666

So, when we say ration station 106 (for example), we're talking about the Bandwidth. And Bandwidth means that this station/channel can be captured on all the frequencies in this band, right?

Peon666

Another related question: When we say that a certain broadband/DSL connection has a bandwidth of say, 1 Mbps, what does that mean?

Thanks.

berkeman

No, when you say FM radio station 98.5, that is the channel centered on 98.5MHz, with a bandwidth of 200kHz.

berkeman

That means that the channel has enough bandwidth to support 1 million bits per second being transmitted through it (with an acceptably low bit error rate).

Peon666

Thanks.

I bit confused about this. Does this mean that the channel is best transmitted at 98.5, but it can be transmitted, with a bit low quality, in the range of 200 kHz bandwidth?

Thanks.

berkeman

No, the transmitted FM signal is centered at 98.5MHz, with signal components (due to the frequency modulation) that extend out +/- 100kHz above and below the center frequency. Check out this info on modulation, and its relation to channel bandwidth:

http://en.wikipedia.org/wiki/Modulation

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Peon666

Thanks a lot! It was really helpful! Taking first course in Analogue Communication. :)