Cisco Model 6940 Four Port Optoelectronic Node 870 MHz 数据表
Model 6940 Collector/Terminator Node - 5-42/54-870 MHz
6
RF Section Specifications, continued
Launch Amplifier Performance - Reverse
Units
Collector Node
Terminator Node
Notes
Operational Gain (minimum)
dB
18
17.5
7,10
Frequency Response
dB
± 0.5
± 0.5
10
Noise Figure
dB
14
14
8,10
Reference Output Levels @ 5 and 42 MHz
dBmV
35
35
5
6 NTSC Channels (CW)
Composite Triple Beat
dB
78
78
Cross Modulation
dB
71
71
Composite Second Order
dB
73
73
Station Performance - Reverse
(Station port input to optical transmitter input)
Units
6940 C/T Reverse
Notes
Amplifier Type
- -
Push Pull
Operational Gain ( minimum)
dB
14
11
Station Delay Characteristics
Forward
(Chrominance to Luminance Delay)
Forward
(Chrominance to Luminance Delay)
Reverse
(Group Delay in 1.5 MHz BW)
(Group Delay in 1.5 MHz BW)
Delay (ns)
Frequency (MHz)
Delay (nS)
Frequency (MHz)
Collector
Terminator
55.25 -58.83
15
5.0 - 6.5
39
58
61.25 -64.83
8
6.5 - 8.0
17
25
67.25 - 70.83
5
8.0 - 9.5
8
15
37.5 - 39.0
15
15
39.0 - 40.5
19
20
40.5 - 42.0
27
28
Notes for RF Section Specifications:
1. Reference output tilt and internal tilt are both “Linear” tilt.
2. Launch amplifier forward noise figure with 0 dB input pad and factory installed 7.5 dB ISEQ.
3. Forward internal tilt specified with factory installed 7.5 dB ISEQ.
4. Launch amplifier forward gain from RF input to station output port, with 0 dB input pad and 7.5 dB ISEQ
5.
2. Launch amplifier forward noise figure with 0 dB input pad and factory installed 7.5 dB ISEQ.
3. Forward internal tilt specified with factory installed 7.5 dB ISEQ.
4. Launch amplifier forward gain from RF input to station output port, with 0 dB input pad and 7.5 dB ISEQ
5.
Reverse output reference level at reverse output of RF launch amplifier.
6.
Station performance can be determined by combining optic performance and launch amplifier performance.
7.
Launch amplifier reverse gain from station reverse input(s) to launch amplifier RF output, with 0 dB reverse input pad, 0 dB
reverse output pad, and 0 dB reverse EQ.
reverse output pad, and 0 dB reverse EQ.
8.
Reverse noise figure at station input port with 0 dB reverse input pad, 0 dB reverse output pad and 0 dB reverse EQ.
9.
Reference output tilt is specified as “linear tilt” (as opposed to traditional “cable tilt”).
10. All reverse specifications are with reverse switch installed.
11. Station reverse gain from station reverse input ports to reverse transmitter input with node in Collector mode. With 0 dB reverse input pad,
11. Station reverse gain from station reverse input ports to reverse transmitter input with node in Collector mode. With 0 dB reverse input pad,
0 dB reverse output pad, and 0 dB reverse EQ in launch amplifier. Station gain equals launch amplifier gain for node in Terminator mode.
12. Subtract this loss from the launch amplifier forward operational gain to determine forward station gain (gain from optical receiver output to
station output).
Unless otherwise noted, the above specifications reflect typical station performance at stated reference levels in the recommended
Operating configuration (s). Unless otherwise noted, specifications are based on measurements made in accordance with NCTA
Recommended Practices for Measurements on Cable Television Systems using standard frequency assignments and are referenced to 68
Operating configuration (s). Unless otherwise noted, specifications are based on measurements made in accordance with NCTA
Recommended Practices for Measurements on Cable Television Systems using standard frequency assignments and are referenced to 68
°F
(20
°C).