PSK transmitter and correlator receiver for UWB communications system

• US 6,724,269 B2
• Filed: 08/06/2002
• Issued: 04/20/2004
• Est. Priority Date: 06/21/2002
• Status: Active Grant

• Current Assignee: Winmark Investments Pte Ltd.
• Original Assignee: Cellonics Incorporated Pte Limited
• Inventors: Joe, Jurianto
• Primary Examiner(s): TON, MY TRANG
• Application Number:
  US10/213,481
• Publication Number:
  US 20030234696A1
• Time in Patent Office: 623 Days
• Field of Search: 331/107.T, 331/108.C, 331/108.D, 375/307, 375/306
• US Class Current: 331/107.00T
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 1/7174 Pulse generation in general H04L25/03834
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 1/7183 Synchronisation
• CPC Class Codes: H04L 27/2039 using microwave technology

Abstract

A circuit to generate antipodal PSK signal and a correlator circuit for recovering information from PSK (phase shift keying) UWB transmissions includes providing a circuit component characterized by a transfer function having alternating stable and unstable regions. By setting the operating point in a stable region or an unstable region, a non-oscillatory or an oscillatory output signal can be produced.

Claims

1. An ultra wideband (UWB) communication system comprising:

an input terminal for receiving a digital signal to be transmitted as a UWB signal;

an antipodal signal generator comprising a first circuit portion having a transfer function characterized by having an unstable operating region bounded by two stable operating regions, the circuit portion producing a first oscillatory signal when being operated in the unstable region, the circuit portion producing a non-oscillatory signal when being operated in the stable region, the antipodal signal generator further comprising a second circuit portion to effect production of a second oscillatory signal that is substantially 180°

out-of-phase relative to the first oscillatory signal; and

an output terminal for producing an antipodal signal comprising first and second oscillatory signals separated by periods of silence, wherein the antipodal signal is suitable for UWB transmission.

2. The system of claim 1 wherein the first circuit portion comprises a first tunnel diode having a first terminal and a second terminal, a first inductive element coupled between the second terminal and a ground reference, and a biasing element coupled between the first terminal and a biasing potential, the first terminal coupled to receive the digital signal, the first oscillatory signal being produced at the second terminal,

wherein the second circuit comprises a second tunnel diode having a third terminal and a fourth terminal, a second inductive element coupled between the fourth terminal and the ground reference, the third terminal coupled to receive the input signal, the second oscillatory signal being produced at the fourth terminal,

the antipodal signal generator further comprising a combining circuit coupled to receive the first and second oscillatory signals to produce the antipodal signal.

3. The system of claim 2 wherein the antipodal signal generator further comprises inverting logic coupled to receive the digital signal and effective to produce an intermediate signal comprising positive-going pulses and negative-going pulses, the positive-going pulses representing a first logic level in the digital signal, the negative-going pulses representing a second logic level in the digital signal.

4. The system of claim 2 wherein the first circuit portion further includes a first capacitive element coupled between the second terminal and the ground reference and the second circuit portion further includes a second capacitive element coupled between the fourth terminal and the ground reference.

5. The system of claim 1 wherein the first circuit portion comprises a tunnel diode having a first terminal and a second terminal, and an inductive element coupled between the second terminal and a ground reference, the antipodal signal generator further including a source of pulses coupled to the first terminal, a mixing component having a first input coupled to the second terminal and a second input coupled to receive the digital signal, the first circuit portion producing an output signal at the second terminal in response to the pulses, the mixing component producing the antipodal signal as a function of the output signal and the digital signal.

6. The system of claim 5 wherein the first circuit further includes a harmonic generation circuit coupled between the second terminal and the first input of the mixing component, the harmonic generation circuit configured to produce a higher harmonic component of the output signal.

7. The system of claim 6 wherein the harmonic generation circuit comprises a filter component to produce the higher harmonic component of the output signal.

8. A signal processing method in a UWB (ultra-wideband) communication system comprising:

receiving a digital signal for transmission;

producing an antipodal signal representative of the digital signal, the antipodal signal comprising first oscillatory signal components and second oscillatory signal components substantially 180°

out of phase relative to the first oscillatory components; and

transmitting the antipodal signal,

the step of producing the antipodal signal including operating a circuit characterized by a transfer function having an unstable operating region bounded by a first stable operating region and a second stable operating region to produce an oscillatory output signal, the first and second oscillatory signal components being based on the oscillatory output signal.

9. The method of claim 8 further including producing a drive signal representative of the digital signal, the driving signal having positive-going pulses and negative-going pulses to represent first and second logic states, respectively, in the digital signal, the step of operating the circuit including driving the circuit with the driving signal, the circuit configured to produce first oscillations when driven by the positive-going pulses of the driving signal, the method further including driving an additional circuit with the driving signal, the additional circuit characterized by a transfer function having an unstable operating region bounded by a first stable operating region and a second stable operating region and configured to produce second oscillations when driven by the negative-going pulses of the driving signal, the first oscillations being substantially 180°

out of phase relative to the second oscillations, the first and second oscillatory signal components being based respectively on the first and second oscillations.

10. The method of claim 8 further including driving the circuit with a pulse signal to produce an output signal comprising periods of oscillations and periods of silence, and modulating the output signal with the digital signal to produce the antipodal signal.

11. The method of claim 8 further including producing higher harmonics of the oscillatory output signal, wherein the first and second oscillatory signal components are based on one of the higher harmonics.

12. A signal processing method in a UWB (ultra wideband) communication system comprising:

receiving a transmitted signal to produce a received signal, the transmitted signal representative of a digital signal;

providing an oscillatory signal; and

mixing the received signal with the oscillatory signal to produce an output signal representative of the digital signal,

wherein providing the oscillatory signal includes driving a first circuit so that it operates repeatedly in a first stable region of operation and then in an unstable region of operation and then in a second stable region of operation and then in the unstable region and then in the first stable region.

13. The method of claim 12 wherein the step of driving the first circuit includes providing a pulse train to an input of the first circuit.

14. The method of claim 12 wherein the step of driving the first circuit includes biasing the first circuit with a DC offset.

15. The method of claim 12 further including varying a phase of the oscillatory signal phase relative to a phase of the received signal.

16. The method of claim 12 wherein the first circuit comprises a tunnel diode having an anode terminal and a cathode terminal, and an inductive element coupled between the cathode terminal and a reference potential, wherein the step of driving the first circuit includes one of applying a pulse train to the anode terminal or applying a DC offset to the anode terminal, wherein the oscillatory signal is based on an output signal at the cathode terminal.

17. A UWB (ultra wideband) system comprising:

a receiver configured to detect a transmitted signal, the receiver having a receiver output to produce a received signal representative of the detected transmitted signal;

a signal generator having a signal output; and

mixer having a first input coupled to the receiver output and a second input coupled to the signal output, the mixer having a mixer output to produce a signal representative of data contained in the transmitted signal,

the signal generator including a first circuit characterized by having an unstable region of operation bounded by first and second stable regions of operation, the signal output being based on an output of the first circuit.

18. The system of claim 17 wherein the first circuit comprises a tunnel diode having an anode terminal and a cathode terminal, and an inductive element, wherein the inductive element is coupled between the cathode terminal and a reference potential, wherein the signal generator includes a pulse source coupled to the anode terminal to feed a pulse train to first circuit.

19. The system of claim 18 wherein the reference potential is ground potential.

20. The system of claim 17 wherein the first circuit comprises a tunnel diode having an anode terminal and a cathode terminal, and an inductive element, wherein the inductive element is coupled between the cathode terminal and a reference potential, wherein the anode terminal is coupled to a DC offset.

21. A UWB (ultra-wideband) communication system comprising:

means for receiving a transmitted signal to produce a received signal, the transmitted signal representative of a digital signal;

first circuit means for producing oscillatory signals, the first circuit means characterized by a transfer function having an unstable region of operation bounded by a first region of stable operation and a second region of stable operation;

a drive source coupled to drive the first circuit means to produce oscillatory signals; and

a mixer having a first input coupled to receive the oscillatory signals from the first circuit means, having a second input coupled to receive the received signal, and having an output representative of the digital signal.

22. The system of claim 21 wherein the first circuit means comprises a tunnel diode having an anode terminal in electrical communication with the drive source and having a cathode terminal in electrical communication with the mixer, and an inductive element coupled between the cathode terminal and a reference potential.

23. The system of claim 22 wherein the drive source is a series of pulses.

24. The system of claim 23 wherein the drive source further includes means for delaying or advancing the series of pulses based on a phase of the received signal.

25. The system of claim 22 wherein the drive source is a DC offset.

26. The system of claim 21 wherein the received signal is an antipodal signal.