1

This unit will have no RF output.

This unit will have no RF output.

2

The receiver will not function below this DC level which is equal to -10 dBm.

• The optimum light level input is -6 to 2 dBm.

• For every 1 dBm change in optical input power, the RF output will change by 2 dB.

• Excessively high light input levels (> +2 dBm) will cause distortions and/or damage the photo diode.

The receiver will not function below this DC level which is equal to -10 dBm.

• The optimum light level input is -10 to -2 dBm.

• For every 1 dBm change in optical input power, the RF output will change by 2 dB.

• Excessively high light input levels (> -2 dBm) will cause distortions and/or damage the photo diode.

1

If the green LED is Off, it is outside optical input range. Green (On) indicates that light is present and the optical input value is higher than -10 dBm.

If the green LED is Off, it is outside optical input range. Green (On) indicates that light is present and the optical input value is higher than -14 dBm.

2

The recommended RF output level at the output of the receiver module is 27 dBmV (+7.0 dBmV as measured at the -20 dB RF test point). This setup is recommended to achieve the best possible performance.

The recommended RF output level at the output of the receiver module is 27 dBmV (+7.0 dBmV as measured at the -20 dB RF test point). This setup is recommended to achieve the best possible performance with 8 dB setting.

1

RF drive level to the laser must be set to the laser manufacturer’s specification.

2

It is possible that the distribution module is set up incorrectly. See the pad and equalizer selection charts in Appendix A for correct pad and equalization. The C/N performance will suffer if the RF levels are too low into the first gain stage or the interstage.

3

It is important to monitor the DC level at the receiver module because in the process of cleaning the connectors, the transfer of light through each connector may improve or degrade. The DC reading should degrade if there is a reflection in the path depending on the severity of the core mismatch. Scratches on the surface of the fiber of the connector can cause reflections. Scratched connectors must be replaced.

4

For standard receiver

For low input receiver

Attenuate the light to simulate the amount of light that should be at the node and rerun the C/N performance. Add components into the path one at a time until the problem is found. Change jumpers, couplers, fibers and connectors one at a time, taking C/N measurements after each change.

A phenomenon called “shot noise” will occur if the light level is too high into the receiver. This is noise generated by the photo diode when the light is converted back to RF. An optical input level exceeding +2 dBm at the detector will also generate distortions.

Attenuate the light to simulate the amount of light that should be at the node and rerun the C/N performance. Add components into the path one at a time until the problem is found. Change jumpers, couplers, fibers and connectors one at a time, taking C/N measurements after each change.

A phenomenon called “shot noise” will occur if the light level is too high into the receiver. This is noise generated by the photo diode when the light is converted back to RF. An optical input level exceeding -2 dBm at the detector will also generate distortions.

1

Recommended RF input levels are:

• Headend transmitter module: 14 dBmV

2

For standard receiver

For low input receiver

The range for optical light input level is -6 to +2 dBm which converts to 0.25 to 1.6 V DC. The optimum operating range is -3 dBm to +2 dBm which converts to 0.5 to 1.6 V DC. Levels higher than +2 dBm can cause the photo diode to generate distortions, which add to the distortion performance of the link, effectively degrading the distortion performance.

The range for optical light input level is -10 to -2 dBm which converts to 0.1 to 0.6 V DC. The optimum operating range is -6 dBm to -2 dBm which converts to 0.25 to 0.6 V DC. Levels higher than -2 dBm can cause the photo diode to generate distortions, which add to the distortion performance of the link, effectively degrading the distortion performance.

3

Attenuate the light to simulate the amount of light that should be at the 1.2 GHz GS7000 Node and rerun the distortion performance. If the distortion performance improves, there is too much light. An inline optical attenuator or a coupler with a higher loss can reduce the light, or the laser may have to be replaced with a lower launch power.

4

Attenuate the RF input level into the amplifier by increasing the pad value at the OIB. If the distortion perform improves, there is too much RF.

1

Be sure all unused ports are properly terminated into 75 ohms to prevent mismatches. The frequency response is cumulative and reflects the response of each active device in the link:

• The frequency response for the transmitter is dependent on the transmitter manufacturer's specification.

• The frequency response of the node is ±1.0 dB from 52 MHz to 1218 MHz (for optical receiver and amplifier combined).

2

It is possible that the RF amplifier is set up incorrectly. Always check to see that padding and equalization is correct to ensure proper levels at the inputs to each gain stage. See the pad and equalizer selection charts in Technical Information for correct pad and equalization.

System LEDs

Green - 2 Hz Flash Pattern

Power-on - Initializing

Required - Indicates power good

Green - 4 Hz Flash Pattern

IP acquired via DHCP, synchronizing and acquiring configuration

Required - Indicates remote SSHv2 session possible

Green - Steady

System status good - Connections good

No faults detected

Red - 2 Hz Flash Pattern

Connection fault - No physical connection to CIN or RF interfaces

Loose connection, connector faults, water ingress at connector, wavelength mismatch, etc.

Red - 4 Hz Flash Pattern

Configuration fault - Failed synchronization or failed to receive configuration from Principal CCAP Core

Wrong DHCP configuration, unreachable hosts, failed authentication with CCAP Core, etc.

Red - Steady

System fault - Device cannot initialize

Indicates hardware fault, always indicated by a steadily illuminated LED.

Amber - Various

Warning - RPD operational but operation is imperfect

Vendor-defined LED behavior. May indicate high error rates in CIN or RF ports, marginal operating conditions, etc.

CIN LEDs

Flash Pattern

Per [IEEE 802.3x]

Indicates connection state

Unilluminated

Ethernet port failure or port administratively disabled

Indicates possible port failure or a port which has been configured to be disabled

D-RF LEDs

2 Hz Flash Pattern

Power-on - Downstream RF initializing

At least one pilot and/or alignment tone active

4 Hz Flash Pattern

Channel or channels activated

Awaiting downstream channel set configuration

Steadily Illuminated

Downstream channel set configuration obtained

Downstream channels operational

Unilluminated

RF port fault or RF port mute

Fault detected in RF port or RF port muted by CCAP Core

U-RF LEDs

2 Hz Flash Pattern

At least one upstream channel configuration received (and a MAP was received for that channel), awaiting upstream burst transmissions

Indicates that the RPD has received and applied at least one upstream channel configuration

4 Hz Flash Pattern

First upstream transmission recognized

Indicates at least one CM's burst transmission has been received

Steadily Illuminated

At least one CM has successfully completed upstream ranging

Upstream deemed operational

Unilluminated

Upstream RF port fault or no configuration

Fault detected in US RF port or no configuration received