US 7,068,740 B2 · Processing of modulated signals

Abstract

In response to a first signal having modulation representing information and a modulation index, embodiments of the present invention generate a second signal that differs from the first signal in its modulation index, and demodulate the second signal. In one embodiment, an arrangement having a signal processor is adapted to receive a first signal having modulation representing information and having a first modulation index and to generate, in response to the first signal, a second signal having frequency modulation representing the information and having a second modulation index different from the first modulation index, and a demodulator coupled to the signal processor so as to receive and demodulate the second signal. In another embodiment, a method comprises the steps of providing a first signal having modulation representing information and having a first modulation index; generating, in response to the first signal, a second signal having modulation representing the information and having a second modulation index different from the first modulation index; and demodulating the second signal.

Claims31

Dependent claims

A method comprising the steps of:

(a) providing a first signal having modulation representing information and having a first modulation index;
(b) generating, in response to the first signal, a second signal having modulation representing the information and having a second modulation index different from the first modulation index;
and
(c) demodulating the second signal, wherein:
step (a) includes receiving a third signal having FSK modulation and mixing the third signal to an intermediate frequency to provide the first signal;
step (b) includes processing the first signal in a nonlinear circuit including an amplitude limiter and filtering the output of the nonlinear circuit to enhance the relative strength of the output's third harmonic component;
and
step (c) includes demodulating the third harmonic component.

5 more elements

Dependencies are inferred from the claim text.

Processing of modulated signals

Life of this patent

Processing of modulated signals

Life of this patent

Abstract

Claims31