docsPnmCmDsHistTable
DOCS-PNM-MIB ·
.1.3.6.1.4.1.4491.2.1.27.1.2.9
Object
table
The purpose of the downstream histogram is to provide a measurement of
nonlinear effects in the channel such as amplifier compression and laser
clipping. For example, laser clipping causes one tail of the histogram
to be truncated and replaced with a spike. The CM captures the histogram
of time domain samples at the wideband front end of the receiver (full
downstream band). The histogram is two-sided; that is, it encompasses
values from far-negative to far-positive values of the samples. The
histogram has either 256 or 255 equally spaced bins. These bins typically
correspond to the 8 MSBs of the wideband analog-to-digital converter (ADC).
The histogram dwell count, a 32-bit unsigned integer, is the number of
samples observed while counting hits for a given bin, and may have the
same value for all bins. The histogram hit count, a 32-bit unsigned
integer, is the number of samples falling in a given bin. The CM
reports the dwell count per bin and the hit count per bin. When
enabled, the CM computes a histogram with a dwell of at least 10
million samples at each bin in 30 seconds or less. The CM continues
accumulating histogram samples until it is restarted, disabled or times
out. If the highest dwell count approaches its 32-bit overflow value,
the CM stops counting and sets the docsPnmCmDsHistMeasStatus attribute to
'sampleReady'. The CM reports the start and end time of the histogram
measurement using bits 21-52 of the extended timestamp, which provides
a 32-bit timestamp value with resolution of 0.4 ms and range of 20 days.
This table will have a row for each ifIndex for the modem.
Context
- MIB
- DOCS-PNM-MIB
- OID
.1.3.6.1.4.1.4491.2.1.27.1.2.9- Type
- table
- Status
- current
- Parent
- docsPnmCmObjects
- Siblings
- 9
- Children
- 1
Syntax
No syntax metadata recorded.
Values & Constraints
No enumerated values or constraints recorded.
Related Objects
Sibling Objects
| Object | Type | Syntax | OID |
|---|---|---|---|
| docsPnmCmControlObjects | node | - | .1.3.6.1.4.1.4491.2.1.27.1.2.1 |
| docsPnmCmUsPreEqTable This object provides access to CM upstream pre-equalizer coefficients.
The CM pre-equalizer coefficients and the CMTS upstream adaptive
equalizer coefficient update values, when t… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.10 |
| docsPnmCmDsOfdmSymCapTable 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.
… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.2 |
| docsPnmCmOfdmChanEstCoefTable The purpose of this table is for the CM to report its estimate of the
downstream channel response. The reciprocals of the channel response
coefficients are typically used by the C… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.3 |
| docsPnmCmDsConstDispMeasTable The downstream constellation display provides received QAM
constellation points for display. Equalized soft decisions (I and Q)
at the slicer input are collected over time, possib… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.4 |
| docsPnmCmDsOfdmRxMerTable This item provides measurements of the receive modulation error ratio
(RxMER) for each subcarrier. Each subcarrier RxMER value consists of one
byte which represents the RxMER valu… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.5 |
| docsPnmCmDsOfdmMerMarTable The purpose of this item is to provide an estimate of the MER margin
available on the downstream data channel with respect to a candidate
modulation profile. This is similar to th… | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.6 |
| docsPnmCmDsOfdmFecTable The purpose of the table is to provide a series of codword error rate
measurements on a per profle basis over a set period of time.
This table will have a row for each … | table | - | .1.3.6.1.4.1.4491.2.1.27.1.2.7 |
| docsPnmCmDsOfdmReqMERObjects | node | - | .1.3.6.1.4.1.4491.2.1.27.1.2.8 |
Child Objects
| Object | Type | Syntax | OID |
|---|---|---|---|
| docsPnmCmDsHistEntry The conceptual row of the docsPnmCmDsHistTable. An instance
is dynamically created and exists for an associated ifIndex upon
which the test defined by this table can take place.
… | row | - | .1.3.6.1.4.1.4491.2.1.27.1.2.9.1 |