Status in source: current.
Technical details
{
"smi_kind": "OBJECT-TYPE",
"definition": [
"docsPnmCmDsOfdmSymCapTable",
"OBJECT-TYPE",
"SYNTAX",
"SEQUENCE",
"OF",
"DocsPnmCmDsOfdmSymCapEntry",
"MAX-ACCESS",
"not-accessible",
"STATUS",
"current",
"DESCRIPTION",
"\"The purpose of downstream symbol capture is to provide partial functionality of a network analyzer to analyze the response of the cable plant from the CM's perspective. At the CM, the received I and Q time-domain samples of one full OFDM symbol before the FFT, not including the guard interval, are captured and made available for analysis. This capture will result in a number of data points equal to the FFT length in use, time aligned for receiver FFT processing. The number of captured samples can be reduced for narrower channels if the sampling rate, which is implementation dependent, is reduced. The capture includes a bit indicating if receiver windowing effects are present in the data. The time domain samples are expressed as 16 bit two's complement numbers using s3.12 format. The CM samples are scaled such that the average power of the samples is approximately 1, in order to avoid excessive clipping and quantization noise. Capturing the input and output of the cable plant is equivalent to a wideband sweep of the channel, which permits full characterization of the linear and nonlinear response of the downstream plant. The MAC provides signaling via the PLC Trigger Message to ensure that the same symbol is captured at the CMTS and CM. The Downstream Symbol Capture is controlled by setting the 'docsPnmCmDsOfdmSymTrigEnable' object. The status of the capture is obtained by reading the value of the 'docsPnmCmDsOfdmSymMeasStatus' object. This table will have a row for each ifIndex for the modem. \"",
"REFERENCE",
"\"DOCSIS 3.1 Cable Modem Operations Support System Interface Specification CM-SP-CM-OSSIv3.1, PNM section.\"",
"::=",
"{",
"docsPnmCmObjects",
"2",
"}"
],
"syntax_tree": [
[
"conceptualTable",
[
"row",
"DocsPnmCmDsOfdmSymCapEntry"
]
],
null,
[
"MaxAccessPart",
"not-accessible"
],
[
"Status",
"current"
],
[
"DESCRIPTION",
"The purpose of downstream symbol capture is to provide partial functionality of a network analyzer to analyze the response of the cable plant from the CM's perspective. At the CM, the received I and Q time-domain samples of one full OFDM symbol before the FFT, not including the guard interval, are captured and made available for analysis. This capture will result in a number of data points equal to the FFT length in use, time aligned for receiver FFT processing. The number of captured samples can be reduced for narrower channels if the sampling rate, which is implementation dependent, is reduced. The capture includes a bit indicating if receiver windowing effects are present in the data. The time domain samples are expressed as 16 bit two's complement numbers using s3.12 format. The CM samples are scaled such that the average power of the samples is approximately 1, in order to avoid excessive clipping and quantization noise. Capturing the input and output of the cable plant is equivalent to a wideband sweep of the channel, which permits full characterization of the linear and nonlinear response of the downstream plant. The MAC provides signaling via the PLC Trigger Message to ensure that the same symbol is captured at the CMTS and CM. The Downstream Symbol Capture is controlled by setting the 'docsPnmCmDsOfdmSymTrigEnable' object. The status of the capture is obtained by reading the value of the 'docsPnmCmDsOfdmSymMeasStatus' object. This table will have a row for each ifIndex for the modem."
],
[
"REFERENCE",
"DOCSIS 3.1 Cable Modem Operations Support System Interface Specification CM-SP-CM-OSSIv3.1, PNM section."
],
null,
null,
null
]
}