Quadrature-free RF receiver for directly receiving angle modulated signal
First Claim
1. A demodulator for demodulating an RF signal without IQ processing, comprising:
- a first signal path for recovering phase information contained in the RF signal, comprising;
amplitude influencing circuitry responsive to the RF signal for producing an output signal having amplitude variations at least partially removed; and
a phase detector responsive to the output signal of the amplitude influencing circuitry for recovering phase information contained in the RF signal and outputting a phase signal; and
a second signal path for recovering amplitude information contained in the RF signal and outputting an amplitude signal.
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Accused Products
Abstract
The present invention, generally speaking, provides a quadrature-free RF receiver for directly receiving RF signals such as angle modulated signals. Various embodiments of the receiver use a digital phase detector together with well-known RF components: a limiter, an envelope detector, a slow Automatic Gain Control (AGC) circuit, a fast AGC circuit, etc. Demodulation may be non-coherent or coherent. The approach followed is to handle the underlying non-linearities of the demodulation process within the circuitry itself, rather than relegating the non-linearities to a separate signal processing step as in the prior art. No I and Q signals are obtained, and no coordinate conversions are performed, offering the potential for space savings, increased accuracy, and especially power savings. Depending on the nature of the modulation employed, either circuitry relating to amplitude recovery or circuitry relating to phase recovery may be dispensed with. By comparison, in quadrature systems, at least the mixing step must remain the same regardless of the characteristics of the modulation employed.
32 Citations
18 Claims
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1. A demodulator for demodulating an RF signal without IQ processing, comprising:
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a first signal path for recovering phase information contained in the RF signal, comprising; amplitude influencing circuitry responsive to the RF signal for producing an output signal having amplitude variations at least partially removed; and a phase detector responsive to the output signal of the amplitude influencing circuitry for recovering phase information contained in the RF signal and outputting a phase signal; and a second signal path for recovering amplitude information contained in the RF signal and outputting an amplitude signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A demodulator for demodulating an RF signal without IQ processing, comprising:
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a first signal path for recovering phase information contained in the RF signal, comprising; first amplitude influencing circuitry responsive to the RF signal for producing a first output signal having amplitude variations at least partially removed; and a phase detector responsive to the first output signal of the amplitude influencing circuitry for recovering phase information contained in the RF signal and outputting a phase signal; and a second signal path for recovering amplitude information contained in the RF signal and outputting an amplitude signal. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification