Generalized frequency modulation

• US 8,971,444 B2
• Filed: 08/05/2009
• Issued: 03/03/2015
• Est. Priority Date: 08/05/2009
• Status: Expired due to Fees

• Current Assignee: Aerospace Corporation
• Original Assignee: Aerospace Corporation
• Inventors: Kumar, Rajendra
• Primary Examiner(s): PANWALKAR, VINEETA S
• Application Number:
  US12/536,078
• Publication Number:
  US 20110033003A1
• Time in Patent Office: 2,036 Days
• Field of Search: 375/295, 375/296, 375/297, 375/259, 375/271, 375/285, 375/302, 375/239, 455/91, 455/114.2, 455/114.3, 332/117
• US Class Current: 375/296
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/156 with demodulation using temporal properties of the received signal, e.g. detecting pulse width

Abstract

A receiver may comprise a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component. The receiver may further comprise a digital demodulator. The digital demodulator may comprise at least one processor circuit programmed for applying a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal. Applying the phase differencer may comprise converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time, and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time. The at least one processor circuit of the digital demodulator may also be programmed for applying a four quadrant inverse tangent to the output function to generate the information signal.

Claims

1. A Generalized frequency modulation transmitter configured to generate a modulated signal from an information signal and a carrier signal, the transmitter comprising:

an integrator configured to integrate the information signal with respect to time to generate an integrated information signal;

an FM modulator configured to generate the modulated signal wherein a frequency of the modulated signal corresponds to the integrated information signal, and wherein a derivative of the frequency of the modulated signal corresponds to the information signal;

an up-converter configured to up-convert the modulated signal to the radio frequency (RF) range; and

a power amplifier in electronic communication with an antenna, the power amplifier configured to transmit the up-converted modulated signal.

2. The transmitter of claim 1, further comprising a pre-emphasis filter configured to filter the information signal.

3. The transmitter of claim 1, wherein the integrator comprises a plurality of cascaded integrator stages arranged in series to successively integrate the information signal with respect to time, and wherein the integrated information signal is an integration of the information signal at an order corresponding to the number of cascaded integrator stages.

4. The transmitter of claim 3, wherein the plurality of cascaded integrator stages consists of two stages.

5. The transmitter of claim 1, wherein at least one of the integrator, the FM modulator and the up-converter comprise a digital processor circuit.

6. The transmitter of claim 1, wherein the generation of the modulated signal comprises:

generating first and second baseband phase modulated signals on the basis of an integral of the integrated information signal;

mixing the first baseband phase modulated signal with an in-phase local oscillator signal to generate a first mixed signal;

mixing the second baseband phase modulated signal quadrature phase local oscillator signal to generate a second mixed signal, wherein the modulated signal is derived from a sum including the first mixed signal and the second mixed signal.