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Why intermediate frequency transformers are used in modulation process?
Wiki User
∙ 12y ago
They are used as adjustable bandpass filters in superheterodyne (Google it) recievers. They determine how well you can select the radio station you require, while rejecting those close to it. They work in a fixed frequency range where their characteristics can be optimised.Very many modern radio recievers use some form of the superheterodyne principle though the function of the IF Transformer (ie bandpass filter) can be realised digitally, as in mobile phones for example. For AM radio a bandwidth of 9 KHz at 450KHz is typical.
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∙ 12y ago
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What is intermediate frequency?
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. [1] The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process calledheterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. The intermediate frequency stays the same for all signals, for example 455 kHz in an AM broadcast receiver.Conversion to an intermediate frequency is useful for several reasons. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune. Lower frequency transistors generally have higher gains so fewer stages are required. It's easier to make sharply selective filters at lower fixed frequencies.
How does frequency modulation work?
Frequency modulation (FM) works by taking a signal, such as an audio signal, and using it to modulate a higher frequency (Radio Frequency, RF) carrier. This modulation causes the RF to shift up and down in frequency. The RF remains relatively constant in amplitude, and its shifting frequency represents the original signal.Contrast this with Amplitude Modulation (AM) where the RF is relatively constant in frequency, but its amplitude represents the original signal.In order to recover the original signal in an FM system, the receiver must demodulate the signal by measuring the time between successive waves of the RF. In a typical broadcast band system, limitations in the the design requirements for tuning the modulated carrier and for demodulating the original signal force the tuning and demodulation to be done in different stages. Using a process known as superhetrodyning, the tuner amplifies the RF with a broad-band amplifier and mixes the RF with a local oscillator (LO) frequency, converting the RF into an intermediate frequency (IF), typically 10.7 MHz. It then passes the still modulated IF (or shifted RF) into a sharp band-pass filter, the IF stage, and removes the interference of other stations from the IF signal. It then demodulates the original signal from the IF signal.Often, the original signal contains encoded information, such as a stereo subcarrier, which is subsequently demodulated and demultiplexed in order to recover the stereo signal. The question, however, asked about frequency modulation, so the answer stops here. If further detail is required, either add it by refining the answer, or comment on the question, and I or someone will refine the answer.
What is difference between modulated wave and carrier wave?
Carrier Wave: A carrier wave is a high-frequency electromagnetic wave that is used as the "carrier" or the base signal in a modulation process. It is typically a pure sine wave with a constant frequency and amplitude. The carrier wave by itself does not carry any information; it serves as a vehicle to carry the information from one location to another. In AM and FM radio broadcasting, the carrier wave is the primary signal transmitted by the radio station. Modulated Wave: A modulated wave is the result of combining the carrier wave with an information signal, such as an audio signal or data. Modulation is the process of varying the characteristics of the carrier wave (either its amplitude or frequency) in accordance with the information signal. There are two common types of modulation: Amplitude Modulation (AM) and Frequency Modulation (FM). In AM, the amplitude of the carrier wave is varied in proportion to the amplitude of the information signal. This variation encodes the information onto the carrier wave. In FM, the frequency of the carrier wave is varied in proportion to the amplitude of the information signal. This variation encodes the information onto the carrier wave. The modulated wave contains the information that needs to be transmitted, and it can be demodulated at the receiving end to retrieve the original information.
Why the carrier for the amplitude modulation must be a sinusoidal waveform?
The wave in amplitude modulation must be a sine wave. A sine wave represents smooth repetitive oscillation, which is necessary for this process.
Why you need modulation?
It might be helpful to have a working definition of modulation before making a statement as to why it is needed. In fact, with an understanding of what modulation is, it will be obvious why it is included in electronic communications.Modulation is the "message" or the "intelligence" that is impressed on a radio frequency (RF) carrier. When we transmit a signal, we generate a carrier frequency, and then we modulate it. We "add" the message or the information we wish to transmit by modulating the carrier in some way. There are at least a dozen different modulation schemes ranging from simple to real head scratchers. They either modify the amplitude, the frequency or the phase of the carrier. Let's look at a few.The simplest modulation technique is taking the transmitted signal and turning it on and off. It is "keyed" to send a series of pulses. Morse code uses on-off keying. In this method of modulation, no modification of the RF carrier signal itself is made. It is simply switched on and off. (It could be looked at as amplitude modulation with the carrier either at zero amplitude or at "maximum" amplitude with nothing in between.) A series of pulses can be transmitted. With Morse code, a short "on" period will send a dot or "dit" out. If we extend the "on" period a bit, we can send a dash or "dah" out. Nothing real sophisticated here, but basic and effective communication. There are obvious limits to how fast information can be transmitted with this modulation scheme. (But don't tell the hams who still use it!)Most of us are familiar with AM radio. AM is amplitude modulation. The amplitude of the RF carrier is modified to modulate it. The amplitude of the modulating signal will determine the amount that the amplitude of the carrier is changed. (The volume of the modulation determines how much the amplitude of the carrier is changed. The frequency of the modulating signal determines the rate of change of the amplitude of the carrier. (The frequency of the modulation determines how fast the amplitude of the carrier is changed.). The frequency of the carrier is held constant through all this.How about FM? In frequency modulation, the amplitude of the carrier is constant. It's left alone. But the frequency of the RF carrier is changed. It is swung above and below where it sits (it's assigned center frequency) at a rate proportional to the frequency of the modulating signal, and at an amount proportional to the amplitude of the modulating signal. In FM single sideband, the carrier frequency and the frequencies above the carrier are transmitted and the frequencies below the carrier are suppressed (upper sideband transmission). Or the frequencies below the carrier are transmitted with the carrier and the upper frequencies are suppressed (lower sideband transmission). In conventional television, the video signal is single sideband, suppressed carrier. It's like "regular" upper sideband transmission except the carrier signal is suppressed. Sideband transmission "saves" space on the RF spectrum. And it works because we really don't need "all" of the FM signal to demodulate the signal at the receiver.Other forms of modulation become more complex. CDMA (code division multiple access), TDMA (time division multiple access) and other methods are used in cell phones to modulate the carrier so the digital data stream can be impressed on the carrier.Modulation is the addition of intelligence to a carrier signal. It's the message. Modulation is necessary because the point of communication is getting the message through.A Simple answer:Simply this... Any communications medium: e.g. Free space - radio waves, Air - Sound waves or radio waves, Optical Fibre - Light, Copper Wires Electrical Anergy (with frequency limits of the copper wire construction) is made for a certain type of signal. But if the signal we want to send is not compatible with the medium, then it does not travel well.Modulation changes the information we want to send from it's original form, into one that is more compatable with the medium we are trying to use.For example, your computer speaks digital over a TCP/IP LAN which requires CAT 5 or better rated cables,, but to connect to your internet service provider (ISP), you need to send the signal over the wires of the telephone company (made for voice tones). To make this connection, and ADSL modem (modulator/demodulator) is used to convert the data into audio tones, which pass over the telephone line, and at the far end are converted back to digital to join the service providers network. in the reverse direct the ISP does the same, and the signals are de-modulated, back to data for your network.Or in simple terms, Its about best use of the medium. Everything else is just a away of doing it. And there are a lot of possible ways to choose.
What radios contain intermediate frequency transformers?
AM (amplified modulation) radio contain the intermediate frequency transformer.it has IF to mixed the carrier signal into local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequency are used in superheterodyne radio recievers, in which an incoming signals is shifted to an IF for amplication before final destination is done.
What is frequency modulation detection?
as signals come in a means of extracting the original signal is required from the carrier frequency that process is called demodulation or modulation detection you called
PLL is used for demodulation of?
Carrier signals that carry information by the process of frequency- or phase-modulation.
What does IF mean in an FM circuit?
IF stands for Intermediate Frequency. An intermediate frequency is a frequency which the primary signal or carrier signal signal is changed to in the process of reception or transmission. For example, an FM or frequency modulated radio or FM television tuner uses an intermediate frequency or IF of 10.7 megaHertz, abbreviated mHz. The primary signal of an FM radio may be between 88 to 108 mHz. This signal is processed to 10.7 mHz and then demodulated to an audio signal that human ears can hear. The reason for using an intermediate frequency is that it will not interfere with the primary or carrier frequency. Also, the lower IF frequency is easier to deal with electronically. Commonly used IF frequencies in FM are 10.7 and 5.5 mHz.AM or amplitude modulation commonly uses 455 kiloHertz although others frequencies may be used.
Tell you what an intermediate frequency amplifier do?
The intermediate frequency (IF) amplifier lies between the mixer and the demodulator. The mixer shifts the input radio frequency (RF) signal into the range of the IF amplifier. The IF amplifer is a band pass amplifier, so only RF signals that are the IF frequency distance away from the local oscillator in the mixer can pass through to the demodulator. This process is called the superhetrodyne process.
What is intermediate frequency?
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. [1] The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process calledheterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. The intermediate frequency stays the same for all signals, for example 455 kHz in an AM broadcast receiver.Conversion to an intermediate frequency is useful for several reasons. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune. Lower frequency transistors generally have higher gains so fewer stages are required. It's easier to make sharply selective filters at lower fixed frequencies.
What is up converter in satellite communication?
Every information sent and received through satellite communication has to have an address to enable the communication process of signal delivery and reception. This naming of the signal is made in the form of a specific frequency. For example each TV channel operates on a unique frequency of it's own. When that frequency is called (tuned technically) out of a spectrum in that band, the chosen frequency gets selected. Since satellite transponders operate at very high frequency, modulation of the signal on to the carrier is difficult. Hence modulation is carried out at a much lower frequency. Such modulated signal is raised to the required frequency( name or address as stated above) that supports the satellite band and the transponder. The equipment used to elevate the frequency of the low frequency carrier (known as Intermediate Frequency) to the satellite transponder frequency is UP CONVERTER C.K.Vasudeva Bangalore
What is The process of changing from one key to another?
Modulation
What is difference between encoding and modulation?
encoding means to encode the data generally it uses for security purposes, we encode the data by using some mathematics operations so that no other could get the information. in modulation we also change the input but it is used for the send the signals to a long way. the week frequency signals can not travel to the long way so we superimpose the week frequency signals to the high frequency signals so that it could reach at it destination. the reverse process of encoding is decoding and the reverse process of modulation is demodulation so that we can get our data in a original form.
What is the voltage wave form?
It is positive and negative signal in the frequency of wave form, the voltage of amplitude modulation, that carriers the signal of frequency.In the process of graph showing result ...
What is a module?
It is a standard or unit of measurement.For the source and more detailed information concerning this subject, click on the related links section indicated below.
How does frequency modulation work?
Frequency modulation (FM) works by taking a signal, such as an audio signal, and using it to modulate a higher frequency (Radio Frequency, RF) carrier. This modulation causes the RF to shift up and down in frequency. The RF remains relatively constant in amplitude, and its shifting frequency represents the original signal.Contrast this with Amplitude Modulation (AM) where the RF is relatively constant in frequency, but its amplitude represents the original signal.In order to recover the original signal in an FM system, the receiver must demodulate the signal by measuring the time between successive waves of the RF. In a typical broadcast band system, limitations in the the design requirements for tuning the modulated carrier and for demodulating the original signal force the tuning and demodulation to be done in different stages. Using a process known as superhetrodyning, the tuner amplifies the RF with a broad-band amplifier and mixes the RF with a local oscillator (LO) frequency, converting the RF into an intermediate frequency (IF), typically 10.7 MHz. It then passes the still modulated IF (or shifted RF) into a sharp band-pass filter, the IF stage, and removes the interference of other stations from the IF signal. It then demodulates the original signal from the IF signal.Often, the original signal contains encoded information, such as a stereo subcarrier, which is subsequently demodulated and demultiplexed in order to recover the stereo signal. The question, however, asked about frequency modulation, so the answer stops here. If further detail is required, either add it by refining the answer, or comment on the question, and I or someone will refine the answer.
