Guide to Spectrum and Signal Analysis

Guide to Spectrum and Signal Analysis
Pages 56
Views 869
Downloads : 5 times
PDF Size : 6.6 MiB

Summary of Contents

Guide to Spectrum and Signal Analysis

  • www.anritsu.com | 31As with AM, it is possible to recover the modulating signal. The analyzer is used as a manually tuned receiver (zero span) with a wide IF bandwidth. However, in contrast to AM, the signal is not tuned into the passband center but to one slope of the filter curve as illustrated in Figure 36. Here the frequency variations of the FM signal are converted into amplitude variation (FM to AM conversion). This method is called slope detection and is not widely used on modern spectrum analyzers since many of them have dedicated FM demodulators.The resultant AM signal is then detected with the envelope detector. The detector output is displayed in the time domain and is also available at the video output for application to headphones or a speaker.A disadvantage of this method is that the detector also responds to amplitude variations of the signal. The majority of Anritsu spectrum analyzers can provide FM and AM demodulators. In addition, Anritsu handheld spectrum analyzers include SSB signal demodulation with a beat frequency oscillator (BFO) to reinsert the suppressed carrier.Figure 36