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QAM is used in a variety of communications systems such as Dial-up modems and WiFi. In cable systems, a QAM tuner is linked to the cable in a manner that is equivalent to an ATSC tuner which is required to receive over-the-air (OTA) digital channels broadcast by local television stations when attached to an antenna. Most new HDTV digital ...
A signal sent by an ideal transmitter or received by a receiver would have all constellation points precisely at the ideal locations, however various imperfections in the implementation (such as noise, low image rejection ratio, phase noise, carrier suppression, distortion, etc.) or signal path cause the actual constellation points to deviate ...
The L+R audio can be extracted from either the AM (stage 1) or the PM (stage 2) modulation component. From there, the audio can be readily de-multiplexed (de-muxed) back to 'stereo', a.k.a. Left and Right channels. For additional information, see the attached PDF: "Introduction to the Motorola C-QUAM AM Stereo System". [1]
QAM Mapper: the bit sequence is mapped into a base-band digital sequence of complex symbols. There are 5 allowed modulation modes: 16- QAM , 32-QAM, 64-QAM, 128-QAM, 256-QAM. Base-band shaping: the QAM signal is filtered with a raised-cosine shaped filter, in order to remove mutual signal interference at the receiving side.
ATSC and DVB-T specify the modulation used for over-the-air digital television; by comparison, QAM is the modulation method used for cable. The specifications for a cable-ready television, then, might state that it supports 8VSB (for broadcast TV) and QAM (for cable TV). 8VSB is an 8-level vestigial sideband modulation.
Demodulation is the process of extracting the original information-bearing signal from a carrier wave.A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave. [1]
A USB digital TV receiver with its antenna. A DTV receiver is a set-top box that permits the reception of digital television.Its components are very similar to a desktop PC. The DTV receiver is a vital link in the chain of television syste
Analog QAM is used in: NTSC and PAL analog color television systems, where the I- and Q-signals carry the components of chroma (colour) information. The QAM carrier phase is recovered from a special colorburst transmitted at the beginning of each scan line. C-QUAM ("Compatible QAM") is used in AM stereo radio to carry the stereo difference ...