ABSTRACT:   An AM/FM receiver which demodulates radio signals by computing estimates of spectral parameters of the radio signals. Three spectral parameter estimation circuits are selectively formed from a number of shared circuits according to the type of modulation of the radio signal. In the case of frequency modulated signals, the respective strengths of the desired signal and interfering signals dictate the most favorable circuit configuration. The first estimation circuit calculates the instantaneous amplitude of the radio signal which corresponds to the modulating audio signal of an AM signal, the second estimation circuit calculates the instantaneous frequency of the radio signal which corresponds to the modulating audio signal of an FM signal, and the third estimation circuit calculates the power mean frequency of the radio signal which, when calculated over a short period of time relative to the rate of change of the FM signal, also corresponds to the modulating audio signal.

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Patent No. Inventor Issued Title 3568067 Williford 3 /1971 FREQUENCY DISCRIMINATOR WITH OUTPUT INDICATIVE OF DIFFERENCE BETWEEN INPUT AND LOCAL REFERENCE SIGNALS 3609555 Van Blerkom 9 /1971 DIGITAL FM RECEIVER 3665507 Peil 5 /1972 SIGNAL PROCESSOR FOR RECEPTION OF AMPLITUDE OR FREQUENCY MODULATED SIGNALS 3854099 Kratt 12 /1974 WIDEBAND COHERENT FM DETECTOR EXEMPLARY CLAIM(s): Show all 11 claims What is claimed is: 2. A receiver for producing signals corresponding to the modulating signals of applied frequency modulated radio frequency signals comprising: an antenna; radio frequency amplification means comprising: an input connected to said antenna; an output terminal; and means for generating a signal at said last mentioned output terminal corresponding to a signaal present at said input amplified by a predefined factor; and a demodulation circuit comprising: an input; an output; and means for generating at said demodulation circuit output a signal corresponding to an estimate of the power mean frequency of said applied signal utilizing: a circuit for generating a signal corresponding to the instantaneous power of said applied signal and a circuit for generating a signal corresponding to the instantaneous power frequency product of said applied signal, first and second integrator circuits for integrating said instantaneous power and said instantaneous power frequency product signals and a diviider circuit for providing said estimate of said power mean frequency signal corresponding to the ratio of said integrated power frequency product signal to said integrated instantaneous power signal. RELATED U.S. APPLICATIONS: none FOREIGN APPLICATION PRIORITY DATA: none FOREIGN REFERENCES: none OTHER REFERENCES: P. Bello, Some Techniques for the Instantaneous Real-Time Means, etc., IEEE Trans. on Comm. Tech., vol. 3, No. 3, pp. 285-292. J. Denenberg, The Estimation of Spectral Moments, Ph.D. Dissertation, Illinois Inst. of Tech. PRIMARY/ASSISTANT EXAMINERS: Libman; George H.; ADDED TO DATABASE: Aug. 21, 1996