Method and circuit for down-converting a signal

• US 7,218,907 B2
• Filed: 07/05/2005
• Issued: 05/15/2007
• Est. Priority Date: 10/21/1998
• Status: Expired due to Fees

• Current Assignee: ParkerVision, Inc.
• Original Assignee: ParkerVision, Inc.
• Inventors: Cook, Robert W., Bultman, Michael J., Sorrells, David F., Moses, Charley D. Jr., Looke, Richard C.
• Primary Examiner(s): Gelin; Jean
• Assistant Examiner(s): Bhattacharya; Sam
• Application Number:
  US11/173,021
• Publication Number:
  US 20050272395A1
• Time in Patent Office: 679 Days
• Field of Search: 455/319, 455/318, 455/313, 455/323, 455/333, 455/337, 455/205, 375/340, 375/316, 375/350, 375/324
• US Class Current: 455/319
• CPC Class Codes: H03C 1/62 Modulators in which amplitude of carrier component in output is dependent upon strength of modulating signal, e.g. no carrier output when no modulating signal is present H03C1/28 - H03C1/34, H03C1/46, H03C1/48 take precedence
• CPC Class Codes: H03D 7/00 Transference of modulation from one carrier to another, e.g. frequency-changing H03D9/00, H03D11/00 take precedence; dielectric amplifiers, magnetic amplifiers, parametric amplifiers used as a frequency-changers H03F
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1475 Subharmonic mixer arrangements
• CPC Class Codes: H04B 1/0025 using a sampling rate lower than twice the highest frequency component of the sampled signal for demodulation of angle-modulated signals H03D3/006
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 25/08 Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/14 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/148 using filters, including PLL-type filters
• CPC Class Codes: H04L 27/156 with demodulation using temporal properties of the received signal, e.g. detecting pulse width
• CPC Class Codes: H04L 27/2672 Frequency domain
• CPC Class Codes: H04L 27/3881 using sampling and digital processing, not including digital systems which imitate heterodyne or homodyne demodulation

Abstract

Methods, systems, and apparatuses for down-converting an electromagnetic (EM) signal by aliasing the EM signal are described herein. Briefly stated, such methods, systems, and apparatuses operate by receiving an EM signal and an aliasing signal having an aliasing rate. The EM signal is aliased according to the aliasing signal to down-convert the EM signal. The term aliasing, as used herein, refers to both down-converting an EM signal by under-sampling the EM signal at an aliasing rate, and down-converting an EM signal by transferring energy from the EM signal at the aliasing rate. In an embodiment, the EM signal is down-converted to an intermediate frequency (IF) signal. In another embodiment, the EM signal is down-converted to a demodulated baseband information signal. In another embodiment, the EM signal is a frequency modulated (FM) signal, which is down-converted to a non-FM signal, such as a phase modulated (PM) signal or an amplitude modulated (AM) signal.

Claims

1. A method for down-converting an electromagnetic signal, comprising:

periodically coupling an electromagnetic signal that includes a carrier signal to an energy storage device and a load, wherein the periodic couplings occur at a rate less than twice the frequency of the carrier signal;

providing, during the periodic couplings, energy from the electromagnetic signal to the energy storage device, thereby changing an amount of energy stored by the energy storage device;

providing, during the periodic couplings, energy from the electromagnetic signal to the load; and

providing, between the periodic couplings, energy from the energy storage device to the load, thereby changing the amount of energy stored by the energy storage device;

whereby the energy provided to the load forms a down-converted signal.

2. The method of claim 1, wherein the periodic couplings have a duration greater than a quarter cycle of the carrier signal.

3. The method of claim 1, wherein the periodic couplings have a duration equal to a half cycle of the carrier signal.

4. The method of claim 1, wherein the periodic couplings have a duration substantially equal to a half cycle of the carrier signal.

5. The method of claim 1, wherein the periodic couplings have a duration just equal to a half cycle of the carrier signal.

6. The method of claim 1, wherein the electromagnetic signal comprises an amplitude modulated signal.

7. The method of claim 1, wherein the electromagnetic signal comprises a frequency modulated signal.

8. The method of claim 1, wherein the electromagnetic signal comprises a phase modulated signal.

9. The method of claim 1, wherein the energy provided to the load forms an intermediate frequency signal.

10. The method of claim 1, wherein the energy provided to the load forms a baseband signal.

11. The method of claim 1, wherein the energy storage device comprises a capacitor.

12. The method of claim 1, wherein the periodic couplings are achieved using a switching device.

13. A method for down-converting an electromagnetic signal that includes a carrier signal using a circuit that includes an energy storage device, a switch, and a load, wherein the switch and the load are coupled in parallel between a port of the energy storage device and a circuit node, the method comprising:

alternately closing and opening the switch at a frequency less than twice the frequency of the carrier signal;

providing, during each of the closings of the switch, energy from the electromagnetic signal to the energy storage device, thereby changing an amount of energy stored by the energy storage device; and

providing, during each of the openings of the switch, energy from the energy storage device to the load, thereby changing the amount of energy stored by the energy storage device;

whereby the energy provided to the load forms a down-converted signal.

14. The method of claim 13, further comprising:

providing, during each of the openings of the switch, energy from the electromagnetic signal to the load.

15. The method of claim 13, wherein each of the closings of the switch has a duration greater than a quarter cycle of the carrier signal.

16. The method of claim 13, wherein each of the closings of the switch has a duration equal to a half cycle of the carrier signal.

17. The method of claim 13, wherein each of the closings of the switch has a duration substantially equal to a half cycle of the carrier signal.

18. The method of claim 13, wherein each of the closings of the switch has a duration just equal to a half cycle of the carrier signal.

19. The method of claim 13, wherein the electromagnetic signal comprises an amplitude modulated signal.

20. The method of claim 13, wherein the electromagnetic signal comprises a frequency modulated signal.

21. The method of claim 13, wherein the electromagnetic signal comprise a phase modulated signal.

22. The method of claim 13, wherein the energy provided to the load forms an intermediate frequency signal.

23. The method of claim 13, wherein the energy provided to the load forms a baseband signal.

24. The method of claim 13, wherein the energy storage device comprises a capacitor.