GOOD2USE Knowledge Network PC Sub-Carrier

GOOD2USE Knowledge Network PC Sub-Carrier

Good Knowledge Is Good2Use

A sub-carrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. A sideband is a band of frequencies higher than or lower than the carrier frequency,. They carry the information (modulation) transmitted by the signal. The sidebands consist of all the Fourier components of the modulated signal except the carrier. All forms of modulation produce sidebands.
Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast.

There is no physical difference between a carrier and a sub-carrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.
For example transmitting information by amplitude modulating the signal carriers results in a modulating signal that covers a frequency range, fmin to fmax to produce an AM wave which consists of a carrier at the chosen frequency, f, and a pair of sidebands which cover the frequency range from f - f_max to f + f_max

The sidebands of transmissions that have similar carrier frequencies mustn't 'overlap'. If each broadcast uses a transmission bandwidth of no more than 9 kHz centred on the chosen carrier frequency, then with a carrier spacing of 9 kHz this means that transmitted sidebands won't overlap and make the receiver's task impossible.

In effect, each modulated transmission is confined to its allocated channel. Theoretically this means that a receiver can always select the transmission it wants and reject all the rest.

In practice, however, there aren't enough channels to go around so the same channel may be allocated to transmitters which are long way apart. This means that the receiver may pick up co-channel interference from far away transmitters that share the same channel.

Search Knowledge Base

Feedback

If you like our web site refer a friend.
Your friends name.	Your friends email address.
Your Name	Your Email Address