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What is the purpose of limiter stage in a FM broadcast receiver?
Wiki User
∙ 12y ago
It is to reduce interference form impulsive noise and even a.m. transmissions.
If the receiver uses a ratio detector instead of the normal frequency discriminator it will be self limiting, thus eliminating the need for a separate stage.
Wiki User
∙ 12y ago
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Why you use 455kHz frequency as an intermediate frequency in communication?
The intermediate frequency in the superheterodyne receiver is chosen as the desired compromise between sensitivity and selectivity. 455kHz is used in AM broadcast applications, while 10.7mHz is used for FM. The IF stage is tuned for a steep skirt passband at that frequency, allowing only the desired heterodyned (shifted) input signal to make it through to the demodulator.
What is a superheterodyne receiver?
A superheterodyne receiver is a receiver that maximizes both sensitivity and selectivity. Normally, these are conflicting goals, and in a single stage, you can only get one, but not both. The difficulty is that you cannot build a high gain RF stage with enough selectivity to reject adjacent signals. The superheterodyne process solves this problem.First, the RF stage is built for high gain, but it is not very selective. It might have some tunability, i.e. selectivity, but that is not its primary objective.Second, there is a local oscillator that is tuned to a frequency some distance away from the primary signal's carrier. In a standard AM receiver, that distance is 455 KHz; in a standard FM receiver, that distance is 10.7 MHz.Third, the amplified RF signal and the local oscillator are mixed together. Recall from Fourier analysis that when you mix two signals together you get four signals; the two original signals, their sum, and their difference. We are interested in their difference. Basically, the output of the mixer contains the original signal downshifted to either 455 KHz or 10.7 MHz.Fourth, we have an IF stage that is tuned around 455 KHZ or 10.7 MHz. The IF stage is highly optimized for operation at one range of frequencies, and can therefore be highly selective. Usually, the IF stage is three bandpass filters, each tuned slightly differently, so that the end result is a bandpass filter that is wide enough to pass the entire bandwidth of the original signal, 20 KHz for AM and 100 KHz for FM.Fifth, we have the demodulator. At this point, we retrieve the signal and either just amplify it (AM) or further decode it for stereo (FM).The end result is that we got sensitivity in the RF stage and selectivity in the IF stage, along with tunability in the local oscillator. That is the superheterodyne process.A very common type of radio receiver. The output from a simple radio aerial will be of the order of a microvolt or so, and the output desired is a few volts. So an amplification of a million or so is needed. This is achieved by multiple stages of amplification - each generally of less than 100 times. And we need to be able to tune over a range of 3:1 for the Broadcast Band, and perhaps greater for some other bands.For technical reasons concerning the mechanics of tuning, this is more easily achieved at a single frequency - typically about 0.5 MHz. The alternative would be to have the same number of stages of amplification but each with its own tuning. Mechanically much more difficult.So, the incoming signal from the aerial is mixed in a mixer stage, along with an internally generated signal. [This mixer stage is a non-linear process, and as a result, produces a complex output, of both the input frequencies, the sum of them, and the difference between them. ] The difference frequency is selected - the 0.5MHz above.So the mixer stage is followed by several intermediate stages of amplification operating at the 0.5 MHz, - where most of the amplification takes place.This is then followed by a demodulator (detector) stage, which separates the audio signal from the carrier signal. And followed in turn by an audio amplifier stage which feeds the loudspeaker.The 'hetrodyne' part of the name refers to the mixing of the signals at the mixer stage. For radios operating at higher frequencies than the broadcast, the Intermediate stage will commonly operate at 10MHz or so.
What is Bandwidth of RF amplifier?
That depends on its purpose. Some examples:RF amplifier in IF stage of AM radio: 10KHz.RF amplifier in TV set: 6MHz.RF amplifier in IF stage of FM radio: 200KHz.An RF amplifier in a military RADAR set will probably have very narrow bandwidth to reduce jamming possibility, but wide enough to allow for doppler shift of targets.
What is the advantage of two stage amplifier compared to single stage?
In a two stage amplifier the gain (ratio of the output to the input quantity) of the first stage is amplified again in the second stage so the gain of a two stage amp is the product of the gain of two individual stages which is sufficient enough to drive the output device as compared to a single stage amplifier.
In what stage modulation is done in high power AM transmissions?
RF Power stage
What is the purpose of a stage?
the purpose of stage clip is when u get stage fright it helps u
What is the purpose of a stage clip?
the purpose of stage clip is when u get stage fright it helps u
When was the television series 'Rising Damp' originally broadcast?
Rising Damp was first broadcast on British television in 1974 through 1978. It was also a 1971 stage play. It was adapted for TV by Eric Chappell based on the stage play.
What do you call the netting screen at the front of the stage that can be broadcast onto or seen-through?
Scrim.
How can you broadcast from an item with a 3.5mm jack to multiple wireless headphones. Bluetooth. Radio?
A wireless in-ear monitor system can be used to broadcast an audio signal. The 3.5mm audio is connected to a transmitter. Each listener then wears an in-ear receiver belt pack, and connects their own earphones or earbuds into the receiver. These are the systems you see musicians using on stage. A pro system like this isn't cheap, however, with a single transmitter/receiver package (in stereo) selling for at least $500.00. Each additional listener will need a receiver and phones (an additional $300 or so per person). These systems are UHF radio frequency. Bluetooth is not used in this fashion because of its limited range, audio quality and 1-1 pairing topology.
What is the importance of Intermediate Frequency stage of the superheterodyne receiver?
for better output,and low impedance.!@
Which part of a radio receiver separates the audio signal from the carrier?
That's the "detector" or "demodulator" stage.
What is the purpose of the stage clip?
the purpose of stage clip is when u get stage fright it helps u
What is the purpose of requirements analysis stage?
To analyze the requirements.
What is the script contains?
Script refers to a written text. A script contains the written text of a stage play, movie, or broadcast.
What is the purpose of cubing during the prewriting stage?
to collect details
What is the purpose of cubing during the prewritting stage?
to collect details
