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Digital Signal Analysis
What is a QAM Signal
Quadrature Amplitude Modulation (QAM) uses many different
phases known as states: 16, 32, 64, and 256. Each state is defined
by a specific amplitude and phase. This means the generation
and detection of symbols is more complex than a simple phase or
amplitude device. Each time the number of states per symbol is
increased the total data and bandwidth increases. The modulation
schemes shown occupy the same bandwidth (after filtering), but
have varying efficiencies (in theory at least).
QAM — Constellation Diagrams
Constellation diagrams are used to graphically represent the
quality and distortion of a digital signal. In practice, there is
always a combination of modulation errors that may be difficult
to separate and identify, as such, it is recommended to evaluate
the measured constellation diagrams using mathematical and
statistically methods. The following section will provide application
and interpretation information of constellation diagrams of digital
modulated signals.
Содержание AMM-806
Страница 86: ...79 TVCB PC Installation ...
Страница 93: ...86 SMI Installation Torque Patterns 1 Start Here 2 3 4 5 6 1 Start Here 2 3 4 4 PORT 8 PORT ...
Страница 125: ...118 Fiber Optics Fiber Loss vs Path Length Single Mode 1550 nm ...
Страница 156: ...149 Cable TV Channel Format NTSC NTSC Composite Video Waveform ...
Страница 157: ...150 US Frequency Spectrum ...
Страница 158: ...151 FCC Aeronautical Band Frequencies Used for Communication and Navigation ...
Страница 171: ...164 F C x 32 Temperature Conversion Nomograph C F FAHRENHEIT F CELSIUS C 9 5 C F 32 5 9 KELVIN K K C 273 ...
Страница 175: ...168 Common CATV Symbols ...
Страница 176: ...169 Common CATV Symbols ...
Страница 177: ...170 Digital L Band Distribution Symbols ...
Страница 178: ...171 Digital L Band Distribution Symbols ...
Страница 183: ...176 Typical Cable Attenuation Chart in dB 100 Feet 68 F 20 C ...
Страница 187: ...180 Echo Rating Graph ...
Страница 188: ...181 Signal to Interference Limits Non Coherent Carriers ...
Страница 190: ...183 Heterodyne Modulator Analog ...
Страница 191: ...184 Heterodyne Processor Analog ...
Страница 213: ...206 Multiplexers ...
Страница 215: ...208 Antenna Stacking Methods to Increase Received Signal Level NOTE Refer to Antenna Spacing Chart for dimensions ...
Страница 216: ...209 Antenna Spacing Mounting Channelized Antennas on the Same Mast NOTE Refer to Antenna Spacing Chart for dimensions ...
Страница 285: ...Rev 8 0 ...