Genesys Products - Equalize Synthesis Module

  Japan

Genesys Equalize Synthesis quickly generates a variety of analog compensation networks that flatten group delay variations across a communication channel bandwidth, in order to reduce linear phase distortion, error vector magnitude, and uncorrected bit error rate in the underlying analog hardware.

Compensate for Linear Phase Distortion

Communications systems designers are concerned with many system variables, such as spur-free dynamic range, immunity to interference, AM-to-PM of the nonlinear components, and amplitude roll-off at the band edges. However, group delay ripple in the linear portions of the network, especially from aggressive, frequency-selective filtering, leads to phase distortion that is often overlooked, especially in FM and constant-envelope modulation schemes. While the effect of phase distortion is more obvious in older FM systems, it is still present in today's communications systems as a form of EVM degradation, which can affect the raw uncorrected bit error rate of the system. Genesys Equalize helps to compensate for these analog hardware issues so that the system delivers a cleaner IF or baseband signal to the signal processing front-end.

Practical linear RF circuits

Genesys Equalize creates a compensation circuit that is cascaded after your device under test, so that the cascaded combination minimizes group delay variation (figure 1).

To use Genesys Equalize, you first select a device that has unwanted group delay ripple, such as an S-parameter data block, a Genesys subcircuit, or perhaps a synthesized filter or matching network. You then browse different compensation network topologies, and cascade as many sections as are required to flatten the group delay of the original network.

Genesys Equalize provides a wizard with built-in searches and optimization to recommend how many stages are needed for the task(figure 2), or, you can control this directly yourself. You can also account for component Q and match to a real impedance other than 50 ohms, such as for Cable TV amplifiers. If you prefer to equalize only a portion of the channel bandwidth, Genesys Equalize allows you minimize parts count and complexity. You can also bring in measured data from a vector network analyzer, and equalize a real circuit for which you have no schematic. (The Testlink module is often considered for this purpose).

The result is lower group delay degradation and improved system performance, for the price of a few lumped components (figure 3).

How is Genesys Equalize Synthesis available?

• The W1505L Equalize Synthesis module can be easily added to any particular Genesys environment or license key that is current on maintenance.
• It is included in the Designer Pro and Integrated bundles
• It is included in the Genesys Synthesis for ADS and RF Architect for ADS bundles
• Equalize Synthesis was also included in several older Genesys configurations, which are now in their support life. (W1403, W1404, W1405, W1406, W1412, W1413, W1414). Refer to the Bundle Viewer for more details

Genesys Equalize Synthesis interacts with other modules

• Genesys Core is the only software requirement for Equalize Synthesis
• Equalize Synthesis works especially well with
• Match Synthesis
• Filter Synthesis
• S/Filter Synthesis
• Testlink can be used to import measured S-parameter data directly from a vector network analyzer.

Online Demos and Tutorials

• EQUALIZE Walkthrough, March 2003