55
QPSK/QAM Transcoders
QAM Modes
The transcoders have three QAM modes.
NORMAL: The normal QAM mode outputs a 6 MHz QAM
modulated signal.
OFF: The off QAM mode outputs no signal from the module.
(When a module is placed in the QAM OFF Mode, the
STATUS LED indicator will blink).
CW: The CW QAM mode outputs a carrier wave test signal that is
very useful for measuring the output level of the transcoder.
(See the QAM Signal Level Testing section for more detail).
(When a module is placed in the QAM CW Mode, the STATUS
LED indicator will blink).
Additional QT Series QAM Modes.
CW ALL: Puts all QTM or QTM-HD installed in rack chassis into CW
mode for ease of level adjustment.
NORMAL ALL: Puts all QTM or QTM-HD installed in rack chassis
into normal QAM mode.
Output Level
The transcoders features electronic output level control for
each of the single transcoder modules. The output level can be
adjusted in any of the QAM modes listed above. The output level
is displayed and measured as an average value. (See the QAM
Signal Level Testing section for more detail).
The output level range is +30 dBmY to +40 dBmV for the QT
Series. The output level will be the same for a QAM CW or EAS IF
Signal as a QAM normal signal.
Note:
For optimum noise performance, the output level for each
module should be set nominally at the maximum output.
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 ...