A method for triggering upon signal events in an RF test and measurement device, comprising: repeatedly sampling a time-varying signal; generating, over time, a plurality of digital frequency domain spectrums based on the sampling of the time-varying signal; and repeatedly updating a frequency domain bitmap for the time-varying signal by sequentially applying the digital frequency domain spectrums to a data store containing the frequency domain bitmap; characterized in that the method further comprises: triggering a capture of the time-varying signal in response to detection of an occurrence of a pre-defined characteristic in the frequency domain bitmap; wherein the frequency domain bitmap is a two-dimensional grid with cells having specified frequency/power values for frequency and power, and where repeatedly updating the frequency domain bitmap includes, for each one of the digital frequency domain spectrums, incrementing specific cells of the frequency domain bitmap if corresponding values are present in said one of the digital frequency domain spectrums; wherein triggering a capture of the time-varying signal in response to detection of an occurrence of a predefined characteristic in the frequency domain bitmap includes determining, for a selected portion of the frequency domain bitmap, whether a relative rate at which the time-varying signal generates frequency spectrum components in the selected portion of the frequency domain bitmap exceeds a predetermined threshold. repeatedly sampling a time-varying signal; generating, over time, a plurality of digital frequency domain spectrums based on the sampling of the time-varying signal; and repeatedly updating a frequency domain bitmap for the time-varying signal by sequentially applying the digital frequency domain spectrums to a data store containing the frequency domain bitmap; characterized in that the method further comprises: triggering a capture of the time-varying signal in response to detection of an occurrence of a pre-defined characteristic in the frequency domain bitmap; wherein the frequency domain bitmap is a two-dimensional grid with cells having specified frequency/power values for frequency and power, and where repeatedly updating the frequency domain bitmap includes, for each one of the digital frequency domain spectrums, incrementing specific cells of the frequency domain bitmap if corresponding values are present in said one of the digital frequency domain spectrums; wherein triggering a capture of the time-varying signal in response to detection of an occurrence of a predefined characteristic in the frequency domain bitmap includes determining, for a selected portion of the frequency domain bitmap, whether a relative rate at which the time-varying signal generates frequency spectrum components in the selected portion of the frequency domain bitmap exceeds a predetermined threshold. triggering a capture of the time-varying signal in response to detection of an occurrence of a pre-defined characteristic in the frequency domain bitmap; wherein the frequency domain bitmap is a two-dimensional grid with cells having specified frequency/power values for frequency and power, and where repeatedly updating the frequency domain bitmap includes, for each one of the digital frequency domain spectrums, incrementing specific cells of the frequency domain bitmap if corresponding values are present in said one of the digital frequency domain spectrums; wherein triggering a capture of the time-varying signal in response to detection of an occurrence of a predefined characteristic in the frequency domain bitmap includes determining, for a selected portion of the frequency domain bitmap, whether a relative rate at which the time-varying signal generates frequency spectrum components in the selected portion of the frequency domain bitmap exceeds a predetermined threshold.