What is a Spectrum Analyzer?
A spectrum analyzer is a wide band, very sensitive receiver. It works on the principle of “super-heterodyne receiver” to convert higher frequencies (normally ranging up to several 10s of GHz) to measurable quantities. The received frequency spectrum is slowly swept through a range of pre-selected frequencies, converting the selected frequency to a measurable DC level (usually logarithmic scale), and displaying the same on a CRT. The CRT displays received signal strength (y-axis) against frequency ( x-axis). Obviously, signals that are weaker than the background noise could not be measured by a spectrum analyzer. For this reason, the noise floor of a spectrum analyzer in combination with RBW is a vital parameter to be considered when choosing a spectrum analyzer. The received signal strength is normally measured in decibels (dbm). (Note that 0 dBm corresponds to 1 mWatt of power on a logarithmic scale). The primary reasons for measuring the power (in dBm) rather than voltage in Spectrum
