Status in source: current.
Technical details
{
"smi_kind": "OBJECT-TYPE",
"definition": [
"docsPnmCmtsDsOfdmSymCapTable",
"OBJECT-TYPE",
"SYNTAX",
"SEQUENCE",
"OF",
"DocsPnmCmtsDsOfdmSymCapEntry",
"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. At the CMTS, the transmitted frequency-domain modulation values of one full OFDM symbol before the IFFT are captured and made available for analysis. The frequency domain samples are expressed as 16-bit two's complement numbers using s3.12 format. This includes the I and Q modulation values of all subcarriers in the active bandwidth of the OFDM channel, including data subcarriers, pilots, PLC preamble symbols and excluded subcarriers. This capture will result in a number of samples that depends on the OFDM channel width. As examples, for 50 kHz subcarrier spacing in a 192 MHz channel with 204.8 MHz sampling rate, 3800 samples will be captured; for 25 kHz subcarrier spacing in a 192 MHz channel with 204.8 MHz sampling rate, 7600 samples will be captured; for 50 kHz subcarrier spacing in a 24 MHz channel with a reduced sampling rate of 25.6 MHz, 475 samples would be captured. Note: Excluded subcarriers in the guard band on either side of the encompassed spectrum are not captured. 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 'docsPnmCmtsDsOfdmSymTrigEnable' object. The status of the capture is obtained by reading the value of the 'docsPnmCmDsOfdmSymMeasStatus' object. \"",
"REFERENCE",
"\"DOCSIS 3.1 CCAP Operations Support System Interface Specification, CM-SP-CCAP-OSSIv3.1, PNM section.\"",
"::=",
"{",
"docsPnmCmtsObjects",
"1",
"}"
],
"syntax_tree": [
[
"conceptualTable",
[
"row",
"DocsPnmCmtsDsOfdmSymCapEntry"
]
],
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. At the CMTS, the transmitted frequency-domain modulation values of one full OFDM symbol before the IFFT are captured and made available for analysis. The frequency domain samples are expressed as 16-bit two's complement numbers using s3.12 format. This includes the I and Q modulation values of all subcarriers in the active bandwidth of the OFDM channel, including data subcarriers, pilots, PLC preamble symbols and excluded subcarriers. This capture will result in a number of samples that depends on the OFDM channel width. As examples, for 50 kHz subcarrier spacing in a 192 MHz channel with 204.8 MHz sampling rate, 3800 samples will be captured; for 25 kHz subcarrier spacing in a 192 MHz channel with 204.8 MHz sampling rate, 7600 samples will be captured; for 50 kHz subcarrier spacing in a 24 MHz channel with a reduced sampling rate of 25.6 MHz, 475 samples would be captured. Note: Excluded subcarriers in the guard band on either side of the encompassed spectrum are not captured. 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 'docsPnmCmtsDsOfdmSymTrigEnable' object. The status of the capture is obtained by reading the value of the 'docsPnmCmDsOfdmSymMeasStatus' object."
],
[
"REFERENCE",
"DOCSIS 3.1 CCAP Operations Support System Interface Specification, CM-SP-CCAP-OSSIv3.1, PNM section."
],
null,
null,
null
]
}