-- An over-modulated AM signal spreads to occupy excessive RF bandwidth. If it's
not the one you happen to be listening to but it's close, then its outlying products
can lop over into the adjacent channel where they don't belong, and show up as
destructive interference to the one you're trying to hear. If it is the one you're
listening to, then its outlying sidebands typically exceed the bandwidth of your
receiver, and the recovered audio to which you're listening includes excessive
audio distortion.
-- A carrier suppressed AM signal is only a problem if the receiver's beat-oscillator
lacks sufficient stability. The receiver is responsible for providing the carrier locally,
which needs to be very close to phase-locked to the missing carrier for decent
audio, and produces weird-sounding audio indeed if it's far from correct phase, or
wandering.
The best approach to receiving carrier-suppressed AM is to begin by sharp-filtering
the received signal so as to retain only one sideband, since the frequency- and
phase-stability requirements on the local oscillator are actually less stringent for
single-sideband detection. But there you go again with a more complex receiver.
For transmission through a radiowave.
Both are forms of AM but in suppressed carrier a filter is used to attenuate the carrier frequency prior to transmission. This is usually done to reduce the total transmitter power consumption. An ordinary AM radio cannot correctly receive suppressed carrier stations, you must have a receiver that replaces the carrier prior to the detector stage.
Each of the two sidebands can be modulated independently to give two simultaneous communication channels. There would be no point in radiating the carrier, as it carries no information, and would waste transmitter power.
using two subcarriers and a main carrier signalaudio subcarrier is frequency modulated with audiocolor subcarrier is phase modulated with chromamain carrier is amplitude modulated with sum of video and modulated audio subcarrier & color subcarrier; then lower sideband is suppressed by a filter.closed captions are serial ASCII encoded characters embedded in vertical blanking of video signal
With full double sideband AM the bandwidth of the modulated signal is twice that of the baseband information signal. With suppressed carrier single sideband AM the bandwidth of the modulated signal is identical to that of the baseband information signal. With vestigial sideband AM the bandwidth of the modulated signal is somewhere between the above two cases, depending on how much of the vestigial sideband is included.
No, the carrier signal is not present at the output of double side band suppressed carrier. That is what suppressed carrier means. However, the receiver has enough information to regenerate the carrier if need be. The advantage of suppressed carrier mode is that more power can be deployed to the signal-carrying portion of the modulated carrier.
radio an amplitude-modulated wave in which only the sidebands are transmitted, the carrier being removedhttp://dictionary.reference.com/browse/suppressed+carrier+modulation
For transmission through a radiowave.
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.
Both are forms of AM but in suppressed carrier a filter is used to attenuate the carrier frequency prior to transmission. This is usually done to reduce the total transmitter power consumption. An ordinary AM radio cannot correctly receive suppressed carrier stations, you must have a receiver that replaces the carrier prior to the detector stage.
Modulation is where an electronic signal (base) is combined with another electronic signal (carrier).The base could be audio, video or digital. The carrier is the frequency that a receiver (radio or television) is tuned to.The modulated wave is the result of this combination.
Please answerin the case of communication , a balanced modulator is used to suppress the carrier from a conventional amplitude modulated signal
Each of the two sidebands can be modulated independently to give two simultaneous communication channels. There would be no point in radiating the carrier, as it carries no information, and would waste transmitter power.
using two subcarriers and a main carrier signalaudio subcarrier is frequency modulated with audiocolor subcarrier is phase modulated with chromamain carrier is amplitude modulated with sum of video and modulated audio subcarrier & color subcarrier; then lower sideband is suppressed by a filter.closed captions are serial ASCII encoded characters embedded in vertical blanking of video signal
With full double sideband AM the bandwidth of the modulated signal is twice that of the baseband information signal. With suppressed carrier single sideband AM the bandwidth of the modulated signal is identical to that of the baseband information signal. With vestigial sideband AM the bandwidth of the modulated signal is somewhere between the above two cases, depending on how much of the vestigial sideband is included.
A carrier reinsertion oscillator is an electronic circuit used in a radio receiver that is designed to receive single side band carried suppressed radio transmissions. As suggested by the name, in a single side band carried suppressed signal, the carrier signal is suppressed (not transmitted) to save power and/or bandwidth. Before the single side band carried suppressed signal can be decoded to extract the original audio signal, the carrier must first be reinserted. This must be done accurately, otherwise the recovered audio signal will be unintelligible.
yes for transmission of the signal to take place smoothly,digital tranmission needs to be modulated over a carrier