What this Advanced tool adds

This version extends the Basic converter analyser with a formulaic weakly nonlinear analogue-section model. It supports one or two independently configured signals and generates second-, third- and fifth-order harmonics/intermodulation products. Intrinsic converter terms retain the converter image/folding behaviour; analogue IP products are represented once at their real physical frequency, with ADC aliases shown separately in the FPGA spectrum.

IP2 / IP3 / IP5 model

For ADC mode, enter input-referred intercept values (IIP2/IIP3/IIP5). For DAC mode, enter output-referred intercept values (OIP2/OIP3/OIP5). Equal-tone reference laws are P(IM2)=2P−IP2, P(IM3)=3P−2IP3 and P(IM5)=5P−4IP5. Unequal-tone products use the individual signal powers and polynomial product coefficients.

The original F2, F3 and Other Spur entries remain separate: they represent intrinsic converter spurs, while IP2/IP3/IP5 represent the external/analogue signal-path non-linearity.

Signals, bandwidth and jitter

• Each signal has its own centre frequency, dBFS level, occupied bandwidth, PAPR and effective RMS jitter.
• Bandwidth = 0 is treated as CW. Wideband IM product bandwidth is estimated from the contributing signal bandwidths.
• The two effective jitter entries let you model different source/clock contributions. A real converter sampling clock is normally common to both signals.
• PAPR is used for peak/headroom warnings. The model does not infer exact nonlinear spectral statistics from PAPR alone.

ACPR

For wideband signals, ACPR is an engineering estimate. The display distinguishes explicit products in the adjacent windows, per-carrier IP3 regrowth, and composite IP3 regrowth. The worst explicit adjacent-window result is shown first. Set adjacent offset to 0 to use one signal bandwidth as the offset.

How to interpret results

• Nyquist Zone Diagram: wanted signals and intrinsic converter image/fold behaviour across seven zones. Analogue IP2/IP3/IP5 products are shown once at their physical frequency; they are not duplicated as DAC Nyquist images.
• Selected Zone Spectrum: in DAC mode, what appears in the selected physical output zone. In ADC mode, this becomes the 0…Fs/2 FPGA alias spectrum for the selected analogue input-zone setup.
• Levels / Dynamic Metrics: signal/headroom/noise plus strongest IM2/IM3/IM5, in-band distortion, total generated distortion and ACPR estimates. SNIR includes only distortion overlapping the occupied wanted bands; if every enabled signal is CW the noise reference is Fs/2, otherwise it is the sum of enabled non-zero occupied bandwidths, capped at Fs/2.
• Spurious Products / Alias Table: source mechanism, product identity, actual analogue frequency, base alias, shown-zone position, bandwidth and level.
• Floating data boxes: the data boxes on the three graphical plots can be dragged to a clearer position. They include the key signal, noise, IP2/IP3/IP5, IM2/IM3/IM5, SFDR and ACPR information relevant to that view.