Capture controls for compatibility mode are applicable only if the selected CMTS is ServAssure NXT E6000® Converged Edge Router (CER).
NOTE: Some fields retain their values from
previous captures, such as IUC and Service Identifier.
NOTE: Start and end frequency fields are
not supported for this mode.
Capture controls include:Analysis
- Manual
- Allows you to customize your
capture settings. Customizable settings in manual mode include:
- Type
- IUC
- Service Identifier
- Domain
- AWGN
- Additive White Gaussian Noise (AWGN) detects the noise floor for the captured spectrum. AWGN refers to noise that is seen in addition to the signal (Additive, not including non-linear effects), is not frequency-specific (White), and is random (Gaussian).
- Ingress Noise
- Choose this option to detect strong narrow signal leaks into the system.
- Impulse Noise
- Choose this option to detect strong short-lived (impulse) noise that leaks into the system. This noise can include unwanted, nearly instantaneous noise spikes that may be caused by electromagnetic interference. Impulse noise may cause serious error rate issues on data or digital circuits.
Type
- Fullband
- This capture type represents the entire range of frequencies the CMTS can capture. Typically, this is the range from 5MHz to about 100MHz.
- Passband
- For Manual analysis only,
this capture type represents specific frequencies or wavelengths on a
channel. NOTE: Supports Frequency and Time Domain Analysis when using Passband capture.
Interval Usage Code (IUC)
Each upstream transmit burst is part of a class that is given a number called the IUC.
- Any
- Requests any type of burst, such as short or long.
The remaining IUC options are for manual analysis only:
- Request
- An interval used for Request messages from a modem.
- Reqdata
- An interval used for Request or data messages from a modem. This is for multicast messages and is generally not used.
- Initial
- An interval used for Initial ranging requests from a modem attempting to register.
- Station
- An interval used by modems for periodic station maintenance messages.
- Short
- An interval used for short data bursts from modems. This type is used on TDMA channels.
- Long
- An interval used for long data bursts from modems. This type is used on TDMA channels.
- ACK
- An interval used by modems to send acknowledgment messages. It is only used by DOCSIS 1.1 and older devices and is deprecated.
- A-short
- An interval used for short data bursts on ATDMA (Advanced-Phy) channels.
- A-long
- An interval used for long data bursts on ATDMA (Advanced-Phy) channels.
- A-ugs
- An interval used for data
bursts using the Unsolicited Grant Service (UGS) on ATDMA (Advanced-Phy)
channels. This interval type is used for VoIP traffic.NOTE: Values also include IUC with numbers appended to it, such as IUC 12. These are additional IUC codes that have no industry standard definition.
Service Identifier
- IdleFFT
- Idle Fast Fourier Transform (FFT) means that spectrum analysis is captured when no modem should be transmitting and the channel is idle.
The remaining Service Identifier options are for manual analysis only:
- IdleICB
- IdleICB is when Ingress noise cancellation is inactive.
- Any
- Analysis can occur at any time without waiting for the appropriate IUC interval.
Domain
- Frequency
- Amplitude measured versus frequency (MHz).
- Time
- Selectable when Type is Fullband, Amplitude measured versus time (μs).
Capture Interval
- Capture Interval
- The number of seconds between samples. Value range is 0-10 seconds.
Sample Count
- Sample Count
- The number of samples in the
FFT. Possible values include:
- 256
- 512
- 1024
- 2048
- 4096
This field is required for FFT.NOTE: Captures may have a variable resolution based on the sample count chosen (determined by the vendor device).