Communications signal amplifiers having independent power control and amplitude modulation

• US 20060052068A1
• Filed: 08/19/2005
• Published: 03/09/2006
• Est. Priority Date: 04/11/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Tropian, Inc. (Panasonic Holdings Corporation)
• Inventors: Sander, Wendell B., McCune, Earl W. Jr., Meck, Ronald A.
• Granted Patent: US 7,515,885 B2
• Time in Patent Office: Days
• US Class Current: 455/108
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03G 3/004 Control by varying the supply voltage
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

The present invention, generally speaking, provides methods and apparatus for producing an amplitude modulated communications signal, in which a constant-envelope carrier signal is modified in response to a power control signal to produce a modified constant-envelope carrier signal. The modified constant-envelope carrier signal is amplified in response to an amplitude modulation signal to produce a communications signal having amplitude modulation and having an average output power proportional to a signal level of the modified constant-envelope carrier signal. This manner of operation allows wide dynamic range of average output power to be achieved. Because amplitude modulation is applied after amplitude varying circuitry used to produce the modified constant-envelope carrier signal, the amplitude modulation is unaffected by possible non-linearities of such circuitry. In accordance with another aspect of the invention, operation in the foregoing manner at comparatively low average output power levels is combined with switch mode operation at comparatively high average output power levels, enabling high overall efficiency to be achieved. Hence, the disclosed modulator and amplifier combination, in addition to supporting very low power signals, also supports high power signals.

Claims

1. A method of producing an amplitude modulated communications signal using an amplifier having at least one stage including a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising:

applying a carrier signal to the signal input terminal; and

applying a power supply input signal to the power supply input terminal, the power supply input signal being derived at least in part from an amplitude modulation signal,

wherein the one stage produces the amplitude modulated communications signal in response to the carrier signal and the amplitude modulation signal, a signal magnitude of the amplitude modulated communications signal at a given instant being dependent on both to a signal magnitude of the carrier signal and to a signal magnitude of the power supply input signal.

2. The method of claim 1, wherein the carrier signal is angle modulated.

3. The method of claim 2, wherein an average output power of the amplitude modulated communications signal is determined at least in part by a signal magnitude of the carrier signal, and amplitude modulation of the amplitude modulated communications signal is separately determined by the amplitude modulation signal.

4. The method of claim 3, wherein the power supply input signal is derived from both the amplitude modulation signal and a power level control signal.

5. The method of claim 2, comprising controlling the signal magnitude of the carrier signal using an amplitude varying circuit.

6. The method of claim 5, comprising, for at least one desired average output power level, controlling the signal magnitude of the carrier signal and the signal magnitude of the power supply input signal such that the one stage is operated in switch mode.

7. The method of claim 5, wherein the amplifier has multiple series-coupled stages, including the one stage, following the amplitude varying circuit, the method comprising operating each of the multiple stages in triode mode.

8. The method of claim 7, wherein another stage preceding the one stage includes a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising producing a power supply input signal for the other stage in accordance with a desired average output power level and applying the same to the power supply input terminal of the other stage.

9. The method of claim 8, wherein a further stage preceding the one stage includes a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising applying the power supply input signal for the other stage to the power supply input terminal of the further stage.

10. The method of claim 7, comprising, for at least one desired average output power magnitude, controlling the signal level of the carrier signal and the signal magnitude of the power supply input signals such that each of the stages is operated in switch mode.

11. The method of claim 1, wherein a final amplifier stage is coupled to an output network, further comprising maintaining a single configuration of the load network across lowest power and highest power operation.

12-26. -26. (canceled)

27. A method of producing a communications signal, comprising:

modifying a constant-envelope carrier signal in response to a power control signal to produce a modified constant-envelope carrier signal; and

amplifying the modified constant-envelope carrier signal in response to an amplitude modulation signal to produce a communications signal having amplitude modulation and having an average output power proportional to a signal level of the modified constant-envelope carrier signal.

28-47. -47. (canceled)

48. A method of producing an amplitude modulated communications signal using an amplifier having at least one stage including a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising:

applying a carrier signal to the signal input terminal;

based on the step of applying the carrier signal, operating the amplifier in a non-switch mode; and

applying a power supply input signal to the power supply input terminal, the power supply input signal being derived at least in part from an amplitude modulation signal,

wherein the one stage produces the amplitude modulated communications signal in response to the carrier signal and the amplitude modulation signal, a signal magnitude of the amplitude modulated communications signal at a given instant being dependent on a signal magnitude of the carrier signal and a signal magnitude of the power supply input signal.

49. A method of producing an amplitude modulated communications signal using an amplifier having at least one stage including a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising:

applying a carrier signal to an amplitude varying-circuit to produce an amplitude-scaled carrier signal;

applying the amplitude-scaled carrier signal to the signal input terminal;

applying a power supply input signal to the power supply input terminal, the power supply input signal being derived at least in part from an amplitude modulation signal,

wherein the one stage produces the amplitude modulated communications signal in response to the carrier signal and the amplitude modulation signal,

the amplitude of the amplitude modulated communications signal being responsive to both;

the variation between the amplitude of the carrier signal and the amplitude of the amplitude scaled carrier signal, and

the power supply input signal.

50. A method of producing an amplitude modulated communications signal using an amplifier having at least one stage including a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising:

controlling the signal magnitude of a carrier signal using an amplitude varying circuit, the carrier signal comprising an angle modulated signal;

applying the carrier signal to the signal input terminal,;

applying a power supply input signal to the power supply input terminal, the power supply input signal being derived at least in part from an amplitude modulation signal,

wherein the one stage produces the amplitude modulated communications signal in response to the carrier signal and the amplitude modulation signal, a signal magnitude of the amplitude modulated communications signal at a given instant being dependent on both to a signal magnitude of the carrier signal and to a signal magnitude of the power supply input signal.

51. A method of producing an amplitude modulated communications signal using an amplifier having at least one stage including a three-terminal active device having a signal input terminal, a signal output terminal, and a power supply input terminal, the method comprising:

applying a carrier signal to the signal input terminal, the carrier signal operating within an amplitude threshold; and

applying a power supply input signal to the power supply input terminal, the power supply input signal being derived at least in part from an amplitude modulation signal,

wherein the one stage produces the amplitude modulated communications signal in response to the carrier signal and the amplitude modulation signal,

a signal magnitude of the amplitude modulated communications signal at a first time dependent on a signal magnitude of the power supply input signal, and the signal magnitude of the amplitude modulated communications signal at a first time dependent on any variance of the amplitude threshold.