In the figure below, the spectrum analyzer displays the frequency spectrum of a periodic square-wave signal. The spectrum analyzer range (span) is set from O Hz to 15 kHz Z. Is the frequency spectrum discrete or continuous? Why? Oscilloscope-XSC1 | In Use List Oscilloscope xsc1O Spectrum Analyzer-XSA Span contro Zero span Full span Enter dB dBm Lin kHz Range: 1 Span: 15 Start: 0 Center: 7.5 End: 15 Time T1 It 27.000 ms T2 +| 27.000 ms Channel 5.000 V 5.000 V 0.000 V Ref: 0 dB kz Resolution freq: kHz T2-T1 0.000 s 58.594 Hz ChannelA Scale: 500 usDiv Scale: 2 V Y pos. (Div): 58.594 Hz X pos.(Div): 0 Start S Reverse Show refer 8.009 kHz 11.936 mV Input O Trigger