0
Why do you use high frequency signals for communication and why not very high frequencies?
Wiki User
∙ 15y ago
Low, medium and high frequencies is ideal for long distance communication but it is very sensitive to QRM and QRN because only amplitude modulation can be used on this part of the RF spectrum, FM modulation is not possible, where in the higher frequencies, FM (Frequency Modulation) is a beter option but with the drawback of distance overland. VHF, UHF and UUHF can't overcome obstacles like hills, mountains and large buildings, only line of site communication can be used here, although it can be used for long distance in open space IE. in outer space, like satellite communication.
Wiki User
∙ 15y ago
Add your answer:
Earn +20 pts
How High pass filter circuits works?
A High Pass Filter is an Electronic Filter that passes high frequency signals but Attenuates (reduces the Amplitude ) of Signals with frequencies lower than the cut-off Frequency
Why 2 wave traps are provided in the substation?
Line trap also is known as Wave trap. What it does is trapping the high frequency communication signals sent on the line from the remote substation and diverting them to the telecom/teleprotection panel in the substation control room (through coupling capacitor and LMU). This is relevant in Power Line Carrier Communication (PLCC) systems for communication among various substations without dependence on the telecom company network. The signals are primarily teleprotection signals and in addition, voice and data communication signals.Line trap also is known as Wave trap. What it does is trapping the high frequency communication signals sent on the line from the remote substation and diverting them to the telecom/teleprotection panel in the substation control room (through coupling capacitor and LMU). This is relevant in Power Line Carrier Communication (PLCC) systems for communication among various substations without dependence on the telecom company network. The signals are primarily teleprotection signals and in addition, voice and data communication signals. The Line trap offers high impedance to the high frequency communication signals thus obstructs the flow of these signals in to the substation busbars. If there were not to be there, then signal loss is more and communication will be ineffective/probably impossible.
Why is the UHF frequency band used for GPS transmissions?
The UHF frequency band used for GPS transmissions for clear reception and sending. UHF or ultra high frequency is meant for radio frequencies between 300MHz and 3GHz. Normal frequencies for GPS transmissions are 1575.42 MHz and 1227.60 MHz. UHF frequency band covers these GPS frequencies.
For satellite communication the frequency should be less than critical frequency?
For satllite communication the frequency should not be less than the critical frequency because in satellite communicaton high frequency is needed which is reflected by satellite but not by the ionosphere.
What is signal bandwidth?
Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth. The signals ranging within the upper limit & lower limit are called bandwidth signals.
Give the difference between LPF and HPF?
LPF is a low pass LTI filter which passes the low frequency signals and reduce the amplitude of the signals with frequencies higher than the cutoff frequency. HPF is high pass LTI filter which passes the high frequencies and reduce the amplitude of the frequencies lower than filter's cutoff frequency.
How High pass filter circuits works?
A High Pass Filter is an Electronic Filter that passes high frequency signals but Attenuates (reduces the Amplitude ) of Signals with frequencies lower than the cut-off Frequency
Can you have a high bass frequency?
Yes, you can have a high bass frequency. Prolonged exposure to high frequencies can cause hearing loss. In audio work, "bass" usually refers to the low frequencies; "treble" refers to higher frequencies.
What is a line trap?
it is a high resistive paralell rezonans circuit which allows to cary signals between to electric station with limited bandwithAnswerLine traps are a large inductors, suspended at the end of a high-voltage transmission line which prevents high-frequency communications/protection signals from travelling beyond that point, by attenuating those signals. The inductive reactance of the inductor presents a high reactance to high-frequency signals but a low reactance to mains frequency (50/60 Hz).
Why do mobile phones use microwaves and not radio waves?
Microwaves ARE radio waves, just very high frequency radio waves.Some newer phones use a higher frequency (800 to 1900 MHz, aka ultra high frequency) to avoid interference from other broadcasting signals and from various types of machinery.* The term "microwave" refers to wavelengths that correspond to frequencies from about 1 GHz (1000 MHz) to 30 GHz, which has been used for line-of-sight communication relay links. Cellphones do not use the same frequencies. (3 to 30 GHz is designated "super high frequency.")
What is the advantages of using intermadiate frequency for satellite system?
There are three advantages to this type of frequency: 1) At very high frequencies (gigahertz), signal processing circuitry performs poorly. So a high frequency signal is converted to a lower intermediate frequency for processing. 2) In receivers that can be tuned to different stations, intermediate frequencies are used to convert the various different frequencies of the stations to a common frequency for processing. Without using intermediate frequencies, all the complicated filters and detectors in a radio or television would have to be tuned in unison each time the station was changed. 3) The primary advantage is that it improves frequency selectivity. In communication circuits, a very common task is to separate out or extract signals or components of a signal that are close together in frequency. This is called filtering. So a narrower bandwidth and more selectivity can be achieved by converting the signal to a lower intermediate frequency and performing the filtering at that frequency. Hope this helps!
What is the need of high frequency transformers?
High-frequency transformers could be transformers operating at frequencies higher than 50 or 60 Hz. An example is the transformers used in transport aircraft power supplies which operate at 400 Hz. This allows a transformer with a given power rating to made made with one eighth the mass of an equivalent transformer for a 50 Hz supply. Another type of high-frequency transformer is the tuned transformers used in radio systems. A tuned transformer passes signals over only a limited band of frequencies so is useful in radio receivers to tune out unwanted signals on different frequencies from the one that is needed.
Why is that AM signals can often be heard behind hills while FM signals cannot?
AM frequencies have long wavelengths, and the ground wave is what is detected. This just decays linearly with distance. FM frequencies are generally about 100 MHz +/- and have small ground waves, but are too high a frequency to be reflected by the ionosphere. They are essentially line-of-sight signals, though occasionally you'll get a little fringing signal.
Which types of electromagnetic waves are used for communication?
Technically all could be used for communication. Although not all may be suited for the use. Here are a few examples: Radio waves - short wave/long wave radio Microwaves - Used for communication of space objects (spacecraft, satellites, radar etc) Infra-red - Used as a wireless communication between devices like mobile phones Ultra Violet - Butterflies use two ultraviolet signals, UV reflectance or absorbance as a communication system X-Rays - High powered telescopes Dont forget fibre optics for the visible part of the spectrum.
What are the properties of infrared waves?
Infrared signals are the electromagnetic radiations with wavelengths longer than the visible light but shorter than the radio waves. Infrared signals, with frequencies from 300 GHz to 400 THz (wavelengths from 1 mm to 770 nm) can be used for the short range communication. Infrared signals, having high frequencies can not penetrate into the walls.By Robert John Smith
Why AM is high frequency in communication why not low frequency?
A.m. can be applied to a carrier of any frequency.
Why do low frequency waves travel longer distances?
High frequencies are more damped by air than low frequencies.
