- Quantum Channel Designer
- This Page
Design analysis with Quantum Channel Designer proceeds in stages, starting with analysis / optimization of the analog channel, followed by analysis / optimization of the end-to-end channel including vendor-specific equalization and clock recovery. Designers can trade off different levels of simulation accuracy versus speed, performing a broad search of thousands of permutations quickly to identify a set of potential solutions for subsequent, more detailed analysis.
During Network Characterization, Quantum Channel Designer determines the impulse response of the unequalized analog network. QCD's internal network solver uses classic, rigorous microwave analysis techniques that run quickly and produce consistently accurate broadband results. Insertion loss and reflection coefficients are automatically computed in addition to other key channel metrics. Graphical results include the network impulse response and S-parameters, which can be viewed using QCD's interactive waveform viewer.
Statistical analysis combines TX/RX equalization with network characterization data, using statistical methods to compute the link's behavior over quadrillions of bits. Statistical simulations using IBIS-AMI models run quickly, allowing thousands of simulation experiments to be run within minutes. Key design metrics are extracted from simulation results and presented in spreadsheet format, allowing designers to quickly identify which combination of channel and SerDes IP parameters merit more detailed analysis. Graphical results are available both as statistical eye plots (color-coded to show probabilities), eye contour plots and data bathtub /clock probability distributions.
Time-domain analysis simulates the link's response to specific bit patterns and encoding schemes. Nonlinear equalization (RX DFE) and detailed clock-recovery behavior are modeled to determine their impact on link behavior. Time-domain simulations run at about 1,000,000 bits/minute and multiple simulations can be run in parallel to increase throughput. Advanced IBIS-AMI models can expose internal model state data to the user - for example, an RX DFE model can expose its tap coefficients, allowing users to see how many cycles DFE taps take to settle and what pattern sensitivity they exhibit. Key design metrics are automatically extracted from time domain simulations and presented in spreadsheet format, allowing designers to quickly identify optimum combinations of channel and SerDes IP parameters.
Quantum Channel Designer crosstalk analysis analyzes how near and far end crosstalk affects the behavior of a victim link. QCD reports the same key performance metrics as with uncoupled analysis, allowing the impact of crosstalk (NEXT/FEXT) to be easily evaluated. Designers can quickly evaluate tradeoffs between link physical spacing, transmitter output power and TX/RX equalization to co-optimize the physical design and SerDes IP configuration. By allowing designers to evaluate their SerDes IP's ability to compensate for channel impairments, QCD gives designers the opportunity to reduce design costs without compromising design reliability.