0
A bandpass signal, xc(t), is a signal whose one-sided energy spectrum is both:
1) centered at a non-zero frequency, fC, and 2) does not extend in frequency to zero (DC).
The two sided transmission bandwidth of a signal is typically denoted by BT Hertz so that
the one-sided spectrum of the bandpass signal is zero except in [fC − BT /2,fC + BT /2]. This
implies that a bandpass signal satisfies the following constraint: BT /2 < fC. Fig. 1.1 shows a
typical bandpass spectrum. Since a bandpass signal, xc(t), is a physically realizable signal it is
real valued and consequently the energy spectrum will always be symmetric around f = 0. The
relative sizes of BT and fC are not important, only that the spectrum takes negligible values
around DC. In telephone modem communications this region of negligible spectral values is only
about 300Hz while in satellite communications it can be many Gigahertz.
Add your answer:
Earn +20 pts
Role of modulation in signal transmission is varying why?
The Role of modulation in signal transmission varies because of what type of signal should be modulated.Then how long it should be travel in air.All these points are considered, when we go before modulation.Suppose we are transmitting vedio signal means it should be only Amplitude Modulated signal.If we transmitting audio signal means it should be Frequency Modulated Signals.So the Role of the modulation is varies in signal transmission.
Mixer circuit used in Amplitude demodulation?
The mixer circuit in a superhetrodyne receiver, used for both AM and FM receivers, is a local oscillator that is tuned to 455 KHz away from the desired signal (AM), or 10.7 MHz away from the signal (FM), followed by a broad band summing amplifier or, more typically, just a pair of diodes, resulting in shifting the RF signal into the IF range. By Fourier analysis, when you add two signals, you get four results, each signal, their sum, and their difference. The IF strip following the mixer, a steep skirt bandpass filter, is tuned to the difference, providing the selectivity necessary for good reception.The preceding RF stage is a semi broad band, partially tuned, bandpass tank/amplifier circuit that simply enhances the input signal, providing sensitivity instead of selectivity.
Advantages of intermediate frequency?
The intermediate frequency, or IF, in a superhetrodyne receiver is used to tune the desired signal. The IF stage is tuned to a specific, fixed frequency, usually 455 kHz for AM and 10.7 MHz for FM. Since the IF stage does not need to be adjustable, it can be designed for high performance, tight bandpass operation. This is far easier to do than creating an adjustable RF stage with tight bandpass operation. Instead, the RF stage is broadband and the IF stage is narrow band. The actual tuning of the receiver is done by varying the local oscillator that is mixed with the radio frequency (RF) signal just upstream of the IF stage. The difference frequency of the output of the mixer is then amplified by the IF stage. The audio information, to be fed to an amplifier and be heard on the speaker, is extracted after the last IF stage - either by a detector in AM or discriminator in FM.
What is the frequncy range of digital signal?
Telephone bandpass is 300Hz to 3000Hz. This is adequate for a recognizable and understandable voice, however the lack of high frequencies makes some people sound different on the phone.Local calls often have a slightly wider bandpass, but long distance calls are sharply filtered to cutoff at exactly 3000Hz, to avoid spillover into adjacent channels during the process of frequency division multiplexing so that many voice connections may be sent on one line (e.g. twisted pair, microwave link, optical fiber) at the same time.
How do you filter rf signals that distort television reception from a rooftop antenna?
There are a number of steps that you can take to prevent this distortion from occuring. But in order for you to know what to do, you should specify a few things, first: a) Do you have an antenna signal amplifier? b) Is it just one or two channels being affected, or is it all of your channels being affected? c) What channels and ranges does your antenna receive? d) What sort of distortion is it? Are adjacent channels bleeding into this one? Are there horizontal streaks and lines appearing? Or is it just an entire screen filled with noise? If all of your channels are affected or wiped out and you have an antenna signal amplifier, it may be that your amplifier's transmitted signal is too strong. Also, it could be interference from an adjacent channel or the FM band. In this case, you may need a bandpass or a bandstop filter. To get a bandpass or bandstop filter, you should probably turn to an electronics provider like Tin Lee Electronics (www.tinlee.com). You can also contact them about your problem and they should be able to help you solve it. In any case, if you could specify the above information, it would be much easier to find an answer to your problem.
What has the author Ljiljana Milic written?
Ljiljana Milic has written: 'Multirate filtering for digital signal processing' -- subject(s): Bandpass Electric filters, Computer simulation, Data processing, Digital techniques, Electric filters, Bandpass, MATLAB, Mathematics, Multiplexing, Signal processing
What has the author Maurice Rozenberg written?
Maurice Rozenberg has written: 'Constant high Q bandpass filters' -- subject(s): Bandpass Electric filters, Electric filters, Bandpass 'A digitally programmable filter' -- subject(s): Digital filters (Mathematics), Digital techniques, Signal processing
What is meant by a bandpass signal?
Band pass refers to a specific range of frequencies requires for transmission of a signal over a appreciable distance for effective communication by applying special modulation techniques for effective transmission of a signal.
What is the difference between baseband and bandpass communication?
Base band signal is transmission of more than single frequency from zero hz to higher frequency components example : base band signal must be modulated to higher frequencies for radio transmission
What is center frequency?
Center frequency refers to the frequency at the midpoint between the upper and lower limits of a bandpass filter or a communication channel. It is a critical parameter in signal processing, telecommunications, and radio frequency engineering as it represents the frequency around which most of the signal energy is concentrated.
What is a SSBSC signal?
Single Side Band Suppressed Carrier. This is a modification of AM (Amplitude Modulation) that both reduces required transmitter power and signal bandwidth. The carrier is first modulated by the signal the same as in ordinary AM, then is sent through a bandpass filter to remove one sideband and the carrier. To demodulate it and recover the original signal the receiver must reinsert the carrier using a BFO (Beat Frequency Oscillator) and Mixer.
Role of modulation in signal transmission is varying why?
The Role of modulation in signal transmission varies because of what type of signal should be modulated.Then how long it should be travel in air.All these points are considered, when we go before modulation.Suppose we are transmitting vedio signal means it should be only Amplitude Modulated signal.If we transmitting audio signal means it should be Frequency Modulated Signals.So the Role of the modulation is varies in signal transmission.
Mixer circuit used in Amplitude demodulation?
The mixer circuit in a superhetrodyne receiver, used for both AM and FM receivers, is a local oscillator that is tuned to 455 KHz away from the desired signal (AM), or 10.7 MHz away from the signal (FM), followed by a broad band summing amplifier or, more typically, just a pair of diodes, resulting in shifting the RF signal into the IF range. By Fourier analysis, when you add two signals, you get four results, each signal, their sum, and their difference. The IF strip following the mixer, a steep skirt bandpass filter, is tuned to the difference, providing the selectivity necessary for good reception.The preceding RF stage is a semi broad band, partially tuned, bandpass tank/amplifier circuit that simply enhances the input signal, providing sensitivity instead of selectivity.
How do you prove the ideal bandpass filter theorem with an inverse Fourier transform?
this question on pic
Why is the car radio affected by the receipt of a text massage on a mobile in close proximity?
The antenna is picking up the transmission of the signal, and then amplifying it. It could be blocked by having a bandpass filter placed at the point where the antenna comes into the radio Because the frequency of the signal of the mobile interferes with the radio reception. Moreover, the signal of the mobile is strong enough to produce noise on all frequencies range of the radio. Even electric motors can produce noise when next to a radio receiver.
Explain Why high Quality factor is needed in RLC Circuits?
the higher the Q the narrower the bandpass or band-rejection. however high Q is not always desirable. for example in receiver IF stages too high a Q will filter out some of the needed modulation bandwidth, destroying signal information.
What is fsk demodulator?
Frequency Shift Keying (FSK) modulation is the process of modulating a digital signal onto a carrier that is composed of one of two frequencies, one frequency for high - and the other frequency for low. FSK demodulation is the process of recovering the original signal by detecting the frequencies involved in the original modulation. Typically, this is done with a bandpass amplifier tuned to one of the two frequencies, followed by a amplitude demodulator. The output is the original signal. It is possible, though often unecessary, to use two bandpass ampliers, one for each frequency, but this is redundant. It is also possible to use a digital signal processing technique to perform a fourier transform on the input signal, but that can be complex and costly. This is the method used in very early modems, up to around 1200 baud. It is also possible, using FSK, to send multiple signals across one line. Simply pick suitable frequencies for each modulation state, and mix the outputs into one consolidated analog signal. On the other end, you have multiple bandpass filters running at the same time and, as long as the chosen frequencies are appropriately spaced apart, they will not interfere. It is also possible to send analog signals with FSK. One particular system I used took six analog signals, converted them to variable duty cycle pulse trains at 10 Hz, FSK modulated them, mixed them all together, sent them over a leased line, reversed the process, and retrieved the six analog signals.
