information previously lost in conventional digital display spectrum analyzers including persistence can now be displayed referring to fig9 there is illustrated the same signal waveform as illustrated in fig1 and 8 but the plot of fig9 was generated in accordance with the 34 lines 34 mode embodiment of the invention i e the 34 dots 34 are connected this trace is illustrated as it would appear on a conventional monochrome digital display in a 34 lines 34 mode plot of this waveform on an actual color crt in accordance with the invention intensity variations in the plurality of traces would be readily apparent the trace of fig9 is illustrated as plotted on a conventional hp 71000a digital display spectrum analyzer equipped with a hp 70900a local oscillator module modified as described above note that the plot of fig9 closely resembles that of fig1 further note that the peak 100 39 34 as well as the subsidiary peaks 110 39 34 are clearly visible more importantly the underpeak 140 39 34 and the ripples 160 39 34 are also quite clearly visible noise 120 39 is also clearly visible and the subsidiary peaks 110 39 34 the underpeak 140 39 34 and the ripples 160 39 34 are easily distinguished from the noise 120 39 34 the traces of fig8 and 9 were reproduced from actual photographs of the waveform as displayed on a hp 71000a digital display spectrum analyzer equipped with.