Abstract: A frequency-modulated ultrashort-wave signal is received, but due to wave-reflection phenomena from physical bodies reflecting towards the receiving antenna is amplitude modulated, this amplitude modulation being dependent upon frequency. Derived from the frequency-modulated signal is a frequency-deviation signal indicating its instantaneous frequency deviation, and also an amplitude-indicating signal indicating its instantaneous amplitude. These can be fed to the x- and y-inputs of an oscilloscope for display of an amplitude versus frequency curve used to generate a quantitative characterization of reception quality, the oscilloscope screen being provided with a horizontal reference axis.

Abstract: A frequency-modulated ultrashort-wave signal is received, but due to wave-reflection phenomena from physical bodies reflecting towards the receiving antenna is amplitude modulated, this amplitude modulation being dependent upon frequency. An amplitude-indicating signal and a frequency-deviation signal are derived from the received frequency-modulated signal and, instead of merely being applied to the x- and y-deflection inputs of an oscilloscope for partly subjective analysis by a skilled analyst, are applied, preferably via low-pass filters, to first and second differentiators, the two output signals of which are transmitted to a divider which produces a differential-quotient signal indicating the rate of change of the amplitude of the frequency-modulated signal with respect to the frequency deviation of the frequency-modulated signal.