Pulse Modulation (Advanced Radar)

Menu Path: MeasSetup > Advanced Radar Measurement Properties > Analysis > Modulation

The Pulse Modulation group lets you choose the types of pulses you want to include within the pulse modulation auto-detection process and report modulation metrics to pulse and statistics tables if detected. You can choose to include any combination of the following modulation types:

 

The 89600 VSA Software can only auto-detect Triangular FM if the detected “Triangular FM Apex” (FM peak) falls between 15% to 85% of the Pulse Top time sample region. This limitation avoids incorrectly mis-detecting noisy or pulse rise/fall edge impaired LFM, CW or Barker pulses as Triangular FM, when the noise or impairment results in an FM peak (apex) occurring within the pulse edge 0% to 15% or 85% to 100% time sample regions. If you have a triangular frequency modulation where the FM Apex falls between 0% to 15%, or 85% to 100% time sample regions, you must enable Triangular FM only (with all other modulation type checkboxes disabled). This allows successful Triangular FM measurements where the FM Apex occurs at the 10% location within the pulse top samples.

Pulse Modulation Metrics

The pulse modulation detected by the 89600 VSA Software is reported within the Pulse Table results as the Modulation result metric. This determines how the frequency and phase reference trace data is calculated for each detected pulse. This in turn affects the reported frequency and phase versus time reference and error trace results.

In addition, the combination of user-enabled Pulse Modulation checkboxes of Continuous Wave, Linear FM, Triangular FM, Barker PhaseBPSK, QPSK, Frank Code and the P1 - P4 Codes affects which modulation type associated performance metrics are reported within the Pulse Table, Current Record Statistics, and Cumulative Statistics tables, as described below.

Trace results affected include:

Performance metric results affected include:

The following Best-Fit FM performance error metric results are only reported when the detected Pulse Modulation is Linear FM or Triangular FM:

The following Best-Fit FM performance error metric results are only reported when the detected Pulse Modulation is Triangular FM:

The following metric results are only reported when the detected Pulse Modulation is Barker Phase, BPSK, QPSK, Frank Code, or P1 - P4 Code.

Valid results are only reported for metrics associated with the per pulse auto-detected Modulation type; all remaining result metrics are reported as invalid *** (NaN) values.