Communications device with adaptive demodulator for PSK and FSK modulations and related methods

• US 9,942,072 B1
• Filed: 01/27/2017
• Issued: 04/10/2018
• Est. Priority Date: 01/27/2017
• Status: Active Grant

• Current Assignee: L3Harris Technologies, Inc.
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Hartless, Mac Lamar, Wynn, Stephen Robert, Kellam, III, George W.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US15/417,450
• Time in Patent Office: 438 Days
• Field of Search: 375269, 375224, 375329, 375331, 375334, 375335, 375271, 375272, 340 104
• CPC Class Codes: H04L 27/14 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits

Abstract

A wireless communications device may include a wireless receiver, and an adaptive demodulator coupled to the wireless receiver. The adaptive demodulator is configured to apply first and second bandpass filters to amplitude information of a received signal at first and second frequency bands, respectively, and classify the received signal as one of a PSK modulation type, a second PSK modulation type, and a third FSK modulation type based upon whether a tone exists in the amplitude information of the received signal in one or more of the first and second frequency bands. The adaptive demodulator is configured to adjust a demodulating parameter based upon a classified modulation type of the received signal.

Claims

1. A wireless communications device comprising:

a wireless receiver; and

an adaptive demodulator coupled to said wireless receiver and configured to

apply first and second bandpass filters to amplitude information of a received signal at first and second frequency bands, respectively,

classify the received signal as one of a first phase-shift keying (PSK) modulation type, a second PSK modulation type, and a third frequency-shift keying (FSK) modulation type based upon whether a tone exists in the amplitude information of the received signal in at least one of the first and second frequency bands, and

adjust at least one demodulating parameter based upon a classified modulation type of the received signal.

2. The wireless communications device of claim 1 wherein said adaptive demodulator is configured to:

classify the received signal as the first PSK modulation type when the tone exists at the first frequency band;

classify the received signal as the second PSK modulation type when the tone exists at the second frequency band; and

classify the received signal as the third FSK modulation type when the tone does not exist at both of the first frequency band and the second frequency band.

3. The wireless communications device of claim 1 wherein said adaptive demodulator is configured to determine whether the tone exists in the amplitude information of the received signal at the first and second frequency bands by comparing the amplitude information of the received signal at the first and second frequency bands to a threshold.

4. The wireless communications device of claim 1 wherein the first and second PSK modulation types comprise quadrature phase shift keying (QPSK) modulation types at different symbol rates;

and wherein the third FSK modulation type comprises a compatible 4-level frequency (C4FM) modulation type.

5. The wireless communications device of claim 1 wherein the at least one demodulating parameter comprises a demodulation filter bandwidth.

6. The wireless communications device of claim 1 wherein the at least one demodulating parameter comprises a phase difference calculation over a symbol.

7. The wireless communications device of claim 6 wherein said adaptive demodulator is configured to determine a plurality of phase difference values when the received signal is the third FSK modulation type, the plurality of phase difference values being integrated over a symbol interval.

8. The wireless communications device of claim 6 wherein said adaptive demodulator is configured to determine a single phase difference value at a symbol rate when the received signal is one of the first and second PSK modulation types.

9. The wireless communications device of claim 1 wherein said adaptive demodulator is configured to apply the first and second bandpass filters, and determine whether the tone exists in the amplitude information of the received signal at the first and second frequency bands using first and second parallel processing paths.

10. A wireless communications device comprising:

a housing;

an antenna carried by said housing;

a wireless receiver carried by said housing and coupled to said antenna; and

an adaptive demodulator carried by said housing and coupled to said wireless receiver and configured to

apply first and second bandpass filters to amplitude information of a received signal at first and second frequency bands, respectively,

classify the received signal as one of a first phase-shift keying (PSK) modulation type, a second PSK modulation type, and a third frequency-shift keying (FSK) modulation type based upon whether a tone exists in the amplitude information of the received signal in at least one of the first and second frequency bands, and

adjust at least one demodulating parameter based upon a classified modulation type of the received signal.

11. The wireless communications device of claim 10 wherein said adaptive demodulator is configured to:

classify the received signal as the first PSK modulation type when the tone exists at the first frequency band;

classify the received signal as the second PSK modulation type when the tone exists at the second frequency band; and

classify the received signal as the third FSK modulation type when the tone does not exist at both of the first frequency band and the second frequency band.

12. The wireless communications device of claim 10 wherein said adaptive demodulator is configured to determine whether the tone exists in the amplitude information of the received signal at the first and second frequency bands by comparing the amplitude information of the received signal at the first and second frequency bands to a threshold.

13. The wireless communications device of claim 10 wherein the first and second PSK modulation types comprise quadrature phase shift keying (QPSK) modulation types at different symbol rates;

and wherein the third FSK modulation type comprises a compatible 4-level frequency (C4FM) modulation type.

14. A wireless communication system comprising:

a transmitter device configured to transmit a signal of unknown modulation type selected from one of a first phase-shift keying (PSK) modulation type, a second PSK modulation type, and a third frequency-shift keying (FSK) modulation type; and

a receiver device comprising a wireless receiver, and

an adaptive demodulator coupled to said wireless receiver and configured to

apply first and second bandpass filters to amplitude information of the signal at first and second frequency bands, respectively,

classify the signal as one of a first phase-shift keying (PSK) modulation type, a second PSK modulation type, and a third frequency-shift keying (FSK) modulation type based upon whether a tone exists in the amplitude information of the signal in at least one of the first and second frequency bands, and

adjust at least one demodulating parameter based upon a classified modulation type of the signal.

15. The wireless communication system of claim 14 wherein said adaptive demodulator is configured to:

classify the received signal as the first PSK modulation type when the tone exists at the first frequency band;

classify the received signal as the second PSK modulation type when the tone exists at the second frequency band; and

classify the received signal as the third FSK modulation type when the tone does not exist at both of the first frequency band and the second frequency band.

16. The wireless communication system of claim 14 wherein said adaptive demodulator is configured to determine whether the tone exists in the amplitude information of the received signal at the first and second frequency bands by comparing the amplitude information of the received signal at the first and second frequency bands to a threshold.

17. The wireless communication system of claim 14 wherein the first and second PSK modulation types comprise quadrature phase shift keying (QPSK) modulation types at different symbol rates;

and wherein the third FSK modulation type comprises a compatible 4-level frequency (C4FM) modulation type.

18. A method for wireless communications comprising:

operating an adaptive demodulator to apply first and second bandpass filters to amplitude information of a received signal at first and second frequency bands, respectively;

operating the adaptive demodulator to classify the received signal as one of a first phase-shift keying (PSK) modulation type, a second PSK modulation type, and a third frequency-shift keying (FSK) modulation type based upon whether a tone exists in the amplitude information of the received signal in at least one of the first and second frequency bands; and

operating the adaptive demodulator to adjust at least one demodulating parameter based upon a classified modulation type of the received signal.

19. The method of claim 18 further comprising:

operating the adaptive demodulator to classify the received signal as the first PSK modulation type when the tone exists at the first frequency band;

operating the adaptive demodulator to classify the received signal as the second PSK modulation type when the tone exists at the second frequency band; and

operating the adaptive demodulator to classify the received signal as the third FSK modulation type when the tone does not exist at both of the first frequency band and the second frequency band.

20. The method of claim 18 further comprising operating the adaptive demodulator to determine whether the tone exists in the amplitude information of the received signal at the first and second frequency bands by comparing the amplitude information of the received signal at the first and second frequency bands to a threshold.

21. The method of claim 18 wherein the first and second PSK modulation types comprise quadrature phase shift keying (QPSK) modulation types at different symbol rates;

and wherein the third FSK modulation type comprises a compatible 4-level frequency (C4FM) modulation type.

22. The method of claim 18 wherein the at least one demodulating parameter comprises a demodulation filter bandwidth.

23. The method of claim 18 wherein the at least one demodulating parameter comprises a phase difference calculation.