Demodulators – Frequency shift keying or minimum shift keying demodulator – Input signal combined with local oscillator or carrier...
Patent
1991-04-26
1995-03-14
Grimm, Siegfried H.
Demodulators
Frequency shift keying or minimum shift keying demodulator
Input signal combined with local oscillator or carrier...
329308, 329325, 329346, 375327, 375376, H03D 300
Patent
active
053980026
ABSTRACT:
A method and apparatus for digitally demodulating a phase or frequency modulated signal using a quadrature mixing circuit to mix the phase or frequency modulated signal with a frequency equal to the carrier frequency of the received modulated signal to produce in-phase component signal (I) and a quadrature component signal (Q) of the received phase or frequency modulated signal which differ in phase by 90 degrees. The I and Q signals are provided via respective low pass filters to a phase to digital converter for generating a digital output signal. The digital output signal is provided to an interface circuit which generates a plurality of phase-change information signals which are provided to a signal processing circuit. The signal processing circuit uses interpolation circuitry to produce a demodulated signal. A further output of the signal processing circuit, i.e. a D.C. signal, is fed back to provide automatic frequency control to an oscillator in the quadrature mixing circuit.
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Bushnell Robert E.
Grimm Siegfried H.
Samsung Electronics Co,. Ltd.
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