222
Digital Signal Analysis
Carrier suppression or leakage is a special type of interference
in which it’s frequency equals the carrier frequency in the RF
channel. Carrier leakage can be superimposed on the QAM signal
in the I/Q modulator. In the constellation diagram, carrier leakage
shows up as a shifting of the signal states corresponding to the
DC components of the I and Q components.
Additive Gaussian noise can disturb the digitally modulated signal
during analog transmission, for instance in the analog channel.
Additive superimposed noise normally has a constant power
density and a Gaussian amplitude distribution throughout the
bandwidth of a channel. If no other error is present at the same
time, the points representing the ideal signal status are expanded
to form circular “clouds”.
Constellation Diagram — 64 QAM signal with
Additive Noise (SNR = 30.0 dB)
(
Note:
This diagram may also be obtained for other types of interference so
that a distinction from noise-produced patterns cannot be made)
Summary of Contents for AMM-806
Page 86: ...79 TVCB PC Installation ...
Page 93: ...86 SMI Installation Torque Patterns 1 Start Here 2 3 4 5 6 1 Start Here 2 3 4 4 PORT 8 PORT ...
Page 125: ...118 Fiber Optics Fiber Loss vs Path Length Single Mode 1550 nm ...
Page 156: ...149 Cable TV Channel Format NTSC NTSC Composite Video Waveform ...
Page 157: ...150 US Frequency Spectrum ...
Page 158: ...151 FCC Aeronautical Band Frequencies Used for Communication and Navigation ...
Page 175: ...168 Common CATV Symbols ...
Page 176: ...169 Common CATV Symbols ...
Page 177: ...170 Digital L Band Distribution Symbols ...
Page 178: ...171 Digital L Band Distribution Symbols ...
Page 183: ...176 Typical Cable Attenuation Chart in dB 100 Feet 68 F 20 C ...
Page 187: ...180 Echo Rating Graph ...
Page 188: ...181 Signal to Interference Limits Non Coherent Carriers ...
Page 190: ...183 Heterodyne Modulator Analog ...
Page 191: ...184 Heterodyne Processor Analog ...
Page 213: ...206 Multiplexers ...
Page 285: ...Rev 8 0 ...