1. Performance. Broadband. Innovation
Rob Crowe Field Applications Engineer Antronix (347)

2. Signal Conditioning at the Tap Drop Levels Optimization
Performance. Broadband. Innovation
Signal Conditioning at the Tap
Drop Levels Optimization

3. Performance. Broadband. Innovation
Let’s Quickly Review Older Design and Explain Loud and Low Talking Modem and Then Conditioning Will Make More Sense…Hopefully!

4. System Node Example (Return ∆ on Plant Side) - Before Conditioning
Performance. Broadband. Innovation
System Node Example (Return ∆ on Plant Side) - Before Conditioning
*Levels- (860M/55M) with 18/10 dBmV 2dB min tilt, 17dBmV Ret In
Each span = 100 foot of .500 cable
Modem Upstream Level 41 39 37 36 30
Cable Loss / / / / .50
Tap Insert Loss / / / / 1.3
Upstream Bell Graph
∆ High Tap to Low Tap =16dB
∆ Modem Upstream High-Low Tap 11dB
∆ +/- 2dB Amplifier Levels = 13dB
∆ +/- 1dB Temperature Change = 14dB
Source-Antronix -Rob Crowe, Rich Gregory

5. So This Design Showed Us
Performance. Broadband. Innovation
So This Design Showed Us
Potential Forward Reverse Issues in Some End of Line
A Wide Delta on Modem Upstream Level
Impact of Wide Upstream Delta
Contains Loud and Low Talkers
Impedes MSOs from altering Return Path Level to achieve BOTH Optimal Return Level AND keeping all Modem Transmit Levels in a Tight Range

6. What are Loud and Low Talkers?
Performance. Broadband. Innovation
What are Loud and Low Talkers?
Originally, the upstream modem TX window was 40-58dBmV
As Modulation Rates Increased and more Return Spectrum was utilized, the Max Transmit dropped to 53dBmV
Most consider >53dBmV “Loud Talker and <40dBmV “Low Talker * Modem
Allowable Upstream Δ 13dB

7. What is Altering Return Path Level ?
Performance. Broadband. Innovation
What is Altering Return Path Level ?
Many systems have designed their return lash ups in the hub to net a certain signal loss
This forces the modems to transmit at a level that will hit the 1st return active at the Optimal Level
Pad adjustments in this lash up will alter the Modem Transmit Levels
Impact of Wide Upstream Delta on Padding ?
Let’s review the Bell Curve to show why adjustments become difficult

8. CM Count Distribution Upstream TX Power
Performance. Broadband. Innovation
CM Count Distribution Upstream TX Power
Low Talkers
Loud Talkers

9. So What Can Be Done Differently?
Performance. Broadband. Innovation

10. Comparison of Standard vs. Conditioned Tap
Performance. Broadband. Innovation
Comparison of Standard vs. Conditioned Tap
Standard Multitap
Signal Conditioned Multitap
Plug-In 10

11. Types of Conditioners Lower Value Taps Diplex – Return Only
Performance. Broadband. Innovation
Types of Conditioners
Lower Value Taps
Higher Value Taps
Diplex – Return Only
Diplex – Fwd Only
Diplex – Block Return
By-Pass

12. Plug-Ins / Packaging Sleeve with Labels
Performance. Broadband. Innovation
Plug-Ins / Packaging Sleeve with Labels

13. Plug in Cable Simulators and Equalizers are Most Commonly Used
Performance. Broadband. Innovation
Plug in Cable Simulators and Equalizers are Most Commonly Used
This is due to the fact that they are ‘NOT DIPLEXED’ which means if an MSO starts at 42M return then goes to 85M and even 200M these plug ins don’t care
Quick Simplified Look at each….

14. Performance. Broadband. Innovation
High Tap Value

15. High Tap Value – Selection & Signal Conditioning Considerations
Performance. Broadband. Innovation
High Tap Value – Selection & Signal Conditioning Considerations
There are 3 main factors to consider:
Forward Output Levels ( Node/Amp & Tap Ports)
Forward Tilt (Highest Ch level – Lowest Ch level)
Return Signal Path Loss (maximum, allowable)
Because taps are located in close proximity to the node/amp, high values are needed to achieve proper signal levels at the subscriber tap ports.
These tap output levels are dictated by the system’s design.
The Highest tap value used MUST satisfy forward level design BUT must also insure modems do not become ‘loud talkers’ AND maintain OPTIMAL PLANT RETURN LEVEL.
Working backwards * Max modem transmit – house loss – Optimal Return Level = Max Tap Value.
Example: (53dBmV – 9dBmV – 17dBmV = 28)
What if my design calls for HIGH Amplifier Outputs & the Tap Value I would require for proper forward tap levels causes Loud Talker?

16. Cable Simulator – Used in Beginning Tap(s)
Performance. Broadband. Innovation
Cable Simulator – Used in Beginning Tap(s)
System Example #1 – Before Conditioning
Excess positive tilt at the tap ports.
‘Loud Talker’ modems from these locations.

17. Cable Simulator – Used in Beginning Tap(s)
Performance. Broadband. Innovation
Cable Simulator – Used in Beginning Tap(s)
System Example #1 - After Conditioning (CS-09)
Tap
Forward
Tilt Comp
Return
Final Results 23
23 + CS-09 = 32dB
9dB
23dB
32dB FWD/23dB RTN

18. Low Tap Value - Signal Conditioners
Performance. Broadband. Innovation
Low Tap Value - Signal Conditioners

19. 1. Cable Equalizer (CE) Plug-In
Performance. Broadband. Innovation
1. Cable Equalizer (CE) Plug-In
CE (Cable Equalizer)
The cable equalizer is used to equalize the entire bandwidth from 5 to 1.2GHz.
It equalizes the forward bandwidth to produce a positive tilt at the Tap.
This results in flatter signals at the subscriber’s POE.
At the same time, the CE adds attenuation to the return path allowing cable modems to operate at higher output levels.
Net result is improved forward system levels & improved C/I (carrier to interference) in the return path.

20. System Example #1 – Before Conditioning
Performance. Broadband. Innovation
System Example #1 – Before Conditioning
FWD REVERSE TILT
LOW MODEM UPSTREAM =
High negative tilt at the tap ports.
Low Talking Modem.
Noise/ingress coming from these tap locations.
As noise is “Funnel Effect”, these locations will bring down the SNR levels for the entire node.

21. System Example #1 – After Conditioning (CE-09)
Performance. Broadband. Innovation
System Example #1 – After Conditioning (CE-09)
POSITIVE FWD TILT
GOOD MODEM UPSTREAM =
Tap
Forward
Tilt Comp
Return
Final Results 8
8dB
9dB
8dB + CE-09 = 17dB
8dB FWD/17dB RTN

22. How Will Conditioners Discussed Improve SNR?
On the High Tap side, the use of a C.S. or H.T. will allow a tap selection that maintains Optimal Return Plant Level.
If a particular System’s Return Amplifiers were optimal with say 20dBmV in and that system had to lower by 3dBmV to ‘cure’ loud talkers…they have sacrificed 3dB SNR.
On the Low Tap side, the use of CE or RA will raise the level of those end of line (EOL) modems, increasing their individual (C/N) carrier to noise (cures low talkers).
Also, there will be additional attenuation in the return path at these low value taps helping to dampen unwanted noise/ingress.
As Return Noise is a ‘Funnel Effect’, if all ‘Low Talkers’ in a given node are cured then an SNR improvement will be obtained.
By insuring both High Tap and Low Tap are fairly symmetrical (both forward and return), the Upstream Delta will be tighter allowing systems to move the whole modem universe as close to ‘Optimal Level’ as Modem Transmit Requirements Will Allow.
Optimal Return Level produces best SNR for that node.
Return plant conditioning is also included under recommended practices within DOCSIS3.0/3.1.

23. Let’s Go Back to Original Design
Performance. Broadband. Innovation
Let’s Go Back to Original Design
Cure ‘Low Talkers’
Provide Better Tilt at Tap
Increase SNR Performance

24. System Node Example (Return ∆ on Plant Side) - Before Conditioning
Performance. Broadband. Innovation
System Node Example (Return ∆ on Plant Side) - Before Conditioning
*Levels- (860M/55M) with 18/10 dBmV 2dB min tilt, 17dBmV Ret In
Each span = 100 foot of .500 cable
Modem Upstream Level 41 39 37 36 30
Ret Cable Loss (2.0dB)
Ret Tap Insert Loss (3.1dB)
Upstream Bell Graph
∆ High Tap to Low Tap =16dB
∆ Modem Upstream High-Low Tap 11dB
∆ +/- 2dB Amplifier Levels = 13dB
∆ +/- 1dB Temperature Change = 14dB
Source-Antronix -Rob Crowe, Rich Gregory

25. System Node Example (Return ∆ on Plant Side)- After Conditioning
Performance. Broadband. Innovation
System Node Example (Return ∆ on Plant Side)- After Conditioning
*Levels- (860M/55M) with 18/10 dBmV 2dB min tilt, 17dBmV Ret In
Each span = 100 foot of .500 cable
Modem Upstream Level 41 39 37 39 39
Ret Cable loss (2.0dB)
Ret Tap Insert Loss (3.1dB)
PLUG IN ( 3 EQ ) ( 9 EQ )
Upstream Bell Graph
∆ High Tap to Low Tap =16dB
∆ Modem Upstream High-Low Tap 4dB
∆ +/- 2dB Amplifier Levels = 6dB
∆ +/- 1dB Temperature Change = 7dB
Source-Antronix -Rob Crowe, Rich Gregory

26. Let’s Use (Node + 0) Design to:
Performance. Broadband. Innovation
Let’s Use (Node + 0) Design to:
Understand High and Low Value Tap Management
Cure Loud and Low Talker
Maintain Tight Forward Level
Maintain Consistent Upstream Level
Provide Positive Tilt at Every Tap
Maximize Tap Cascade Increasing Active Efficiency Reducing Capex
Improve SNR by Adding Return Path Attenuation at E.O.L Taps and Allowing for ‘Optimal Return’ being set by Limiting High Tap Selection.

27. System Node Example w Conditioning (Return ∆ on Plant Side)
Performance. Broadband. Innovation
System Node Example w Conditioning (Return ∆ on Plant Side)
*Levels- (860M/55M) with 18/11 dBmV 4dB min tilt, 13dBmV Ret In, 43dBmV Max Modem Upstream Level at Tap
Node Output
57/42
∆ High Tap to Low Tap =25
∆ Modem Upstream = 15
∆ +/- 2dB Amplifier Levels = 17
∆ +/- 1dB Temperature Change = 18
Source-Antronix -Rob Crowe, Rich Gregory 27

28. System Node Example w Conditioning (Return ∆ on Plant Side)
Performance. Broadband. Innovation
System Node Example w Conditioning (Return ∆ on Plant Side)
*Levels- (860M/55M) with 18/11 dBmV 4dB min tilt, 13dBmV Ret In, 43dBmV Max at Tap
Node Output
57/42
Tap Level
20/ / / / / / / /15
E-Option CS CS CS JMP JMP CE CE CE-09
Modem
Return
∆ High Tap to Low Tap =19dB
∆ Modem Upstream = 2.5dB
∆ +/- 2dB Amplifier Levels = 4.5dB
∆ +/- 1dB Temperature Change = 5.5dB
Source-Antronix -Rob Crowe, Rich Gregory 28

29. Typical Print Notation
Performance. Broadband. Innovation
Identification
Typical Print Notation
Typical Tap Notation
CSG-09

30. Conclusions on Design:
Performance. Broadband. Innovation
Conclusions on Design:

31. Considerations for Network Design Changes
Performance. Broadband. Innovation
Considerations for Network Design Changes
Fwd / Return Spectrum
Node / Amp Output Levels
Hardline Loss
Minimum Tap Levels
Minimum Tilt
Min / Max Modem Tx Level
Conditioning Offers Greater Flexibility
Increasing Design Efficiencies and Reducing Tap Value Skews

32. Performance. Broadband. Innovation
Remember:
A good design starting point is to consider average Installation within footprint. From this you can obtain adequate tap levels that still allow you to push Nodes / Amps as far as they can go. Better symmetry tap to tap for both Fwd/Ret level can result in tighter whole house check specs; reducing repeat TC’s driving Efficiencies and NPS.

33. Quick Side Note on Moca for 1.2G
Performance. Broadband. Innovation
Quick Side Note on Moca for 1.2G

34. Performance. Broadband. Innovation
Will MoCa Still Work?
Yes, but Operator will Have to Use Moca Ch’s above 1218 MHz

35. Performance. Broadband. Innovation
Thanks for Your Time….

36. Performance. Broadband. Innovation

37. Performance. Broadband. Innovation

38. Performance. Broadband. Innovation

39. Performance. Broadband. Innovation