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The program to design and analyze
active quadrature networks

This graphics-intensive program designs and analyzes active quadrature ("90-degree") networks for use in SSB transmitters and receivers.

Here are the highlights of this program:
  • QuadNet is a 32-bit Windows® program to design and analyze active quadrature networks.

  • Enter the lower and upper audio frequencies of interest, along with the network complexity (order) and see the resulting sideband attenuation. Change any of these items to interactively refine your design.

  • Plug in the values for a published design to see how it works.

  • Fine graphics outputs include sideband suppression, the angles for each of the two chains, and the deviation from target.

  • Change or tune the stage time-constants and you can generate a network with sideband suppression which is not uniform across the audio band.

  • Save as an overlay the current-schematic sideband suppression plot, make changes and then recall that stored response for comparison with new data by overlaying the old plotted data on top of the current plot.

  • Use the nearest-value routine to substitute the nearest 5%, 1% or 0.25% values for the program-computed values and see the result.

  • Use the Monte Carlo mode to see what happens when real-world parts are used with user-specified value tolerances.

  • Schematic is shown in graphics form. This is in addition to a conventional "parts list."

  • Handles orders 2 through 18, odd and even.

  • Outputs to the printer are not just screen dumps but are separate high-resolution routines.

  • Writes a nice ready-to-run LTspice file for math confirmation and/or to see the effects of a real-world op-amp (Tonne Software has no connection with Linear Technology).

Here are screen dumps from the program illustrating some of the outputs to the screen. Click on them to see larger versions; use your brower's BACK button to return.

Sideband suppression:
Sideband suppression
Chain angles
Phase error:
Phase error
Parts list:
Parts list
Tabulated output:
Tabulated output
Design entry:
Design entry
Analysis range entry:
Analysis range entry
Monte Carlo entry:
Monte Carlo entry