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Network Characterization Results

Results to View

These are the results data from the Network Characterization phase of the analysis. There is a table of data as well as waveform data to view.

ResultDescription
Impulse Response (Unequalized)Impulse response of the analog channel.
Step Response (Unequalized)The step response of the analog channel.
Pulse Response (Unequalized)The pulse response of the analog channel.
Transfer Function (Unequalized)The transfer function of the analog channel.
S-Parameters (dB)

S-parameters for the analog channel plotted as dB vs. frequency. You can view the data as single ended or mixed mode. You can also view the through path (insertion loss), self path (return loss), and crosstalk.

The nodes are written in the format: S<output mode><input mode>(output port, input port), where the output and input modes are denoted by D for the differential mode and C for the common mode.

S-Parameters (Polar)

S-parameters for the analog channel plotted as real vs. imaginary. You can view them as single ended or mixed mode S-Parameters. You can also view the through path (insertion loss), self path (return loss), and crosstalk.

TDT

Time domain transmission (TDT) data for the analog channel. You can view them as either single ended or mixed mode. You can also view the through path (insertion loss), self path (return loss), and crosstalk.

The nodes are written in the format: T<output mode><input mode>(output port, input port), where the output and input modes are denoted by D for the differential mode and C for the common mode.

Note

The Parallel Link Designer app does not generate TDT.

TDR

Time domain reflectometry (TDR) data for the analog channel. You can view the data as either single ended or mixed mode. You can also view the through path (insertion loss), self path (return loss), and crosstalk.

The nodes are written in the format: T<output mode><input mode>(output port, input port), where the output and input modes are denoted by D for the differential mode and C for the common mode.

Note

The Parallel Link Designer app does not generate TDR.

Export Channel S-Parameter

Save the S-parameters for all channels combined to an external location. You can place multiple S-parameters on a schematic to combine them.

Note

The Parallel Link Designer app supports S-parameters but does not generate them, so you cannot export channel S-parameters from the Parallel Link Designer app.

Probed Impulse ResponseImpulse responses at the probed location(s) of the pre-layout schematic. In a case of parallel link project, the result represents the responses at the receiver B node.
Probed Step ResponseStep responses at the probed location(s) of the pre-layout schematic. In case of parallel link project, the result represents the responses at the receiver B node.
Probed Pulse ResponsePulse responses at the probed location(s) of the pre-layout schematic. In case a of parallel link project, it is the pulse response at the receiver B node.
Probed Transfer FunctionTransfer functions at the probed location(s) of the pre-layout schematic. In case of parallel link project, it is the transfer function at the receiver B node.

Note

The stat mode in the Parallel Link Designer app does not support user-defined probes, but it adds a single probe at the receiver B-node.

Node Locations

The full node names in network characterization contain the designator names. For example, BTX1 is the B node for the designator TX1.

Network characterization probe points.

Table Column Definitions

ParameterDefinition
Transfer NetName of the transfer net for the simulation.
TransferBus transaction (designator from-to) for the simulation.
UI (ps)Unit interval for the transmitted data, defined as the time duration for a single transmitted symbol.
Symbol Rate (Gbps)Rate at which symbols are transmitted on the channel. The delivered payload UI can be lower for an encoding such as 8b10b is used, or higher if a modulation such as PAM4 is used.
Loss (dB)

The difference between the channel loss at DC and the channel loss at a frequency equal to one half the symbol rate.

This parameter is widely used to measure the ease with which you can equalize a channel. As a rule of thumb, <15dB easy, 20dB is moderately challenging, and >25dB is very challenging. 30dB is the upper limit for most technologies, although equalization for higher loss channels has been demonstrated in select sample parts.

The loss is for the analog RX and TX channels.

UnEQ Signal/Xtalk (dB)

Ratio of unequalized signal energy to the combined unequalized energy of all the crosstalk aggressors.

This parameter is a first order indicator of crosstalk problems. A signal to crosstalk ratio of more than 26 dB can be considered safe for a target BER of 10-12, and a ratio of 30 dB can be considered safe in general. Lower ratios indicate that you need to analyze your system design.

Note

This parameter does not show the effect of the Tx Aggressor Factor AMI parameter.

Ripple (dB)

Peak-to-peak deviation of the transmission path dB loss from a straight line, up to a frequency equal to one half the UI.

A large value indicates channel distortion in a channel whose time delay might be beyond the range of available equalizers. This parameter is important primarily for short low-loss channels, and a value of more than about 2 dB is cause for concern.

Ntwk Unequalizable Nrg

Unequalizable Energy from Network Analysis.

This parameter is defined as the amount of energy in the impulse response that cannot be equalized out assuming a transmitter with a four tap FFE and a receiver with a peaking filter and no DFE. This parameter can indicate resonance problems.

Impulse Width (ps)

Time interval between the time when 1% of the impulse response energy has been observed and the time when 99% of the impulse response energy has been observed.

Set the maximum channel delay to a value greater than the sum of the impulse width and the path delay.

DC Loss (dB)

Channel loss of the channel at very low frequencies excluding the effects of AC coupling.

The loss is for the RX and TX channels.

Fc Loss (dB)

Channel loss of the channel at a frequency equal to one half the symbol rate.

The loss is for the RX and TX channels.

SDD11 Return Loss (dB)Return loss presented to the driver by the passive electrical interconnect at a frequency equal to one half the symbol rate.
SDD22 Return Loss (dB)Return loss presented to the driver by the passive electrical interconnect at a frequency equal to one half the symbol rate.
SDD21 Return Loss (dB)SDD21 insertion loss in dB.
SimulationName of simulation file.
CORNERThe process corner for the simulation. For more information, see Specify Corner Conditions in Serial Link Design or Specify Corner Conditions in Parallel Link Design.
Bit_Sequence_SetName of stimulus set from the stimulus file to use in simulation.
Network_CharacterizationSimulation type for network characterization.
Time_DomainSimulation type for time domain simulation.
COLUMNGroup name and value number to use in the simulation. Specify this value when there are variation groups in the solution space.

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