Configurable multi-mode modulation system and transmitter

• US 7,539,462 B2
• Filed: 08/09/2005
• Issued: 05/26/2009
• Est. Priority Date: 08/09/2005
• Status: Active Grant

• Current Assignee: Apple Inc., OGM Laboratory LLC
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Peckham, David S., Traylor, Kevin B., Meador, Richard B.
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): Nguyen, Tu X
• Application Number:
  US11/199,737
• Publication Number:
  US 20070037530A1
• Time in Patent Office: 1,386 Days
• Field of Search: 455/425, 455/550.1, 455/142, 455/143, 455/144, 455/126, 455/108, 455/110, 455/93, 330/85, 330/129
• US Class Current: 455/83
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback

Abstract

A multi-mode transmitter architecture is configurable for multiple modulation modes using either polar or polar-lite modulation. Multiplexed signal paths and reconfigurable components are controlled for performance in GMSK and EDGE burst modes. Polar-lite EDGE modulation is programmed by setting a multiplexer coupling a first amplitude modulated signal path with a frequency modulated signal path input to a dual-mode power amplifier for amplification of the combined EDGE transmission signal. In full-polar EDGE modulation, amplitude modulated signal is multiplexed into a second amplitude modulated signal path for A/D conversion and comparison with a polar feedback signal coupled from the power amplifier output. The resulting comparison is applied to a power control port of the power amplifier to amplitude modulate the EDGE transmission output. Multiplexers are configured to disconnect the amplitude modulated paths when operating in GMSK signaling for both full-polar and polar-lite modulation. Multiplexers selectively couple power feedback into the second amplitude modulated signal path to provide power control and output power ramping for burst transmissions.

Claims

1. A configurable multi-mode modulation system for use in a transmitter, comprising:

a phase modulation path receiving a phase component converted from base band data and frequency modulating the phase component to generate a frequency modulated RF signal on an output;

a first selectable amplitude modulation path receiving an amplitude component converted from base band data and, when the first selectable amplitude modulation path is selected, modulating the amplitude component to generate a first amplitude modulated signal on an output;

a combiner circuit having a first input, a second input and an output coupled to a power amplifier, wherein the first input is coupled to the output of the phase modulation path and the second input is coupled to the output of the first selectable amplitude modulation path, the combiner circuit selectively outputting a first combined signal derived from the frequency modulated RF signal or a second combined signal derived from the first amplitude modulated signal and the frequency modulated RF signal;

a second selectable amplitude modulation path coupled to the converter for receiving the amplitude component and, when the second selectable amplitude modulation path is selected, converting the amplitude component to a second amplitude modulated signal on an output, wherein the first and second selectable amplitude modulation paths are not selected when the modulation system is operating in GMSK modulation; and

a configurable stage having a first input coupled to the output of the second selectable amplitude modulation path, a second input suitable for receiving a feedback signal from an output of the power amplifier, and an output suitable for coupling to a power control input of the power amplifier, wherein, when the second selectable amplitude modulation path is selected, the configurable stage is configured as an integrator for comparing the second amplitude modulated signal and the feedback signal to generate a power control signal on its output, thereby providing amplitude modulation to the power amplifier.

2. The modulation system of claim 1, wherein the first selectable amplitude modulation path is selected when the modulation system is operating in EDGE polar-lite modulation.

3. The modulation system of claim 2, wherein the power amplifier is a dual-mode power amplifier driven in a linear region when the modulator system is operating in EDGE polar-lite modulation.

4. The modulation system of claim 1, wherein the second selectable amplitude modulation path is selected when the modulation system is operating in EDGE full-polar modulation.

5. The modulation system of claim 4, wherein the power amplifier is a non-linear power amplifier driven in a saturated region when the modulator system is operating in EDGE full-polar modulation.

6. The modulation system of claim 1, wherein the first selectable amplitude modulation path further comprises a digital-to-analog converter for converting the received amplitude component to the first amplitude modulated signal.

7. The modulation system of claim 1, wherein the second selectable amplitude modulation path further comprises:

a digital-to-analog converter;

a multiplexer for selectively, when the first selectable amplitude modulation path is selected, coupling the digital-to-analog converter to receive the amplitude component and converting the amplitude component to the second amplitude modulated signal at the first input of the configurable stage.

8. The modulation system of claim 1, further comprising an integrator selectively coupled to the second selectable amplitude modulation path and receiving a power setting signal at a first input indicating a desired output power level for the power amplifier and the feedback signal on a second input.

9. The modulation system of claim 8, further comprising means for selectively fixing the output signal of the integrator to a constant level during a data transmission phase of EDGE polar-lite modulation.

10. The modulation system of claim 1, further comprising means for generating a ramp signal, wherein the ramp signal is coupled to the second selectable amplitude modulation path to adjust the output power of the power amplifier during a ramp phase of full-polar modulation.

11. The modulation system of claim 1, wherein the combiner receives a third input and the third input is a reference voltage, and further wherein the combiner selectively outputs a third combined signal derived from the reference voltage and the frequency modulated RF signal when operating in GMSK and EDGE full-polar modulation.

12. The modulation system of claim 1, wherein said combiner comprises a multiplier.

13. The modulation system of claim 1, further comprising a polar converter receiving base band data and converting it into the phase and amplitude components.

14. A transceiver comprising:

a receiver; and

a transmitter comprising;

a power amplifier, and

a modulator system according to claim 1.

34. A transceiver comprising:

a receiver; and

a transmitter comprising;

a power amplifier, and

a modulator system according to claim 1.

15. A method of providing a transmitter for a selected modulation type, comprising:

selecting one of a first or second modulation type of operation for the transmitter;

providing a frequency modulated path generating a frequency modulated signal;

providing an amplitude modulated path generating an amplitude modulated signal;

if the selected modulation is the first modulation type;

configuring the amplitude modulated path to be combined with the frequency modulated path such that the frequency modulation signal is selectively combined with

the amplitude modulation signal to create a combined signal; and

providing a power amplifier for amplifying the combined signal;

if the selected modulation is the second modulation type;

configuring the amplitude modulated path to couple with a power control input of a power amplifier, whereby the amplitude modulated signal modulates the output power of the power amplifier;

providing a power amplifier for amplifying the phase modulated signal, wherein the output power of the power amplifier is adjusted based upon the amplitude modulated signal; and

if the selected modulation is a third modulation type;

configuring the amplitude modulation path to de-couple from the power amplifier; and

providing a power amplifier for amplifying the phase modulated signal.

16. The method of claim 15, wherein the first modulation type is EDGE polar-lite modulation.

17. The method of claim 15, wherein the second modulation type is EDGE full-polar modulation.

18. The method of claim 15, wherein the third modulation type is GMSK modulation.

19. The method of claim 15, further comprising, when selected modulation is the second modulation type, configuring a feedback path to couple with the amplitude modulation path and generating an error signal from a comparison of the amplitude modulated signal and a feedback signal from the power amplifier output, wherein the error signal is coupled to the power control input of the power amplifier to control the output power of the power amplifier.

20. The method of claim 15, further comprising:

generating a ramp signal;

comparing the ramp signal with a feedback signal from the output of the power amplifier; and

adjusting the output power of the power amplifier based upon the comparison.

21. A configurable multi-mode modulation system for use in a transmitter, comprising:

a phase modulation path receiving a phase component converted from base band data and frequency modulating the phase component to generate a frequency modulated RF signal on an output;

a first selectable amplitude modulation path receiving an amplitude component converted from base band data and, when the first selectable amplitude modulation path is selected, modulating the amplitude component to generate a first amplitude modulated signal on an output;

a combiner circuit having a first input, a second input and an output coupled to a power amplifier, wherein the first input is coupled to the output of the phase modulation path and the second input is coupled to the output of the first selectable amplitude modulation path, the combiner circuit selectively outputting a first combined signal derived from the frequency modulated RF signal or a second combined signal derived from the first amplitude modulated signal and the frequency modulated RF signal, wherein the combiner receives a third input and the third input is a reference voltage, and further wherein the combiner selectively outputs a third combined signal derived from the reference voltage and the frequency modulated RF signal when operating in GMSK and EDGE full-polar modulation;

a second selectable amplitude modulation path coupled to the converter for receiving the amplitude component and, when the second selectable amplitude modulation path is selected, converting the amplitude component to a second amplitude modulated signal on an output; and

a configurable stage having a first input coupled to the output of the second selectable amplitude modulation path, a second input suitable for receiving a feedback signal from an output of the power amplifier, and an output suitable for coupling to a power control input of the power amplifier, wherein, when the second selectable amplitude modulation path is selected, the configurable stage is configured as an integrator for comparing the second amplitude modulated signal and the feedback signal to generate a power control signal on its output, thereby providing amplitude modulation to the power amplifier.

22. The modulation system of claim 21, wherein the first selectable amplitude modulation path is selected when the modulation system is operating in EDGE polar-lite modulation.

23. The modulation system of claim 22, wherein the power amplifier is a dual-mode power amplifier driven in a linear region when the modulator system is operating in EDGE polar-lite modulation.

24. The modulation system of claim 21, wherein the second selectable amplitude modulation path is selected when the modulation system is operating in EDGE full-polar modulation.

25. The modulation system of claim 24, wherein the power amplifier is a non-linear power amplifier driven in a saturated region when the modulator system is operating in EDGE full-polar modulation.

26. The modulation system of claim 21, wherein the first and second selectable amplitude modulation paths are not selected when the modulation system is operating in GMSK modulation.

27. The modulation system of claim 21, wherein the first selectable amplitude modulation path further comprises a digital-to-analog converter for converting the received amplitude component to the first amplitude modulated signal.

28. The modulation system of claim 21, wherein the second selectable amplitude modulation path further comprises:

a digital-to-analog converter;

a multiplexer for selectively, when the first selectable amplitude modulation path is selected, coupling the digital-to-analog converter to receive the amplitude component and converting the amplitude component to the second amplitude modulated signal at the first input of the configurable stage.

29. The modulation system of claim 21, further comprising an integrator selectively coupled to the second selectable amplitude modulation path and receiving a power setting signal at a first input indicating a desired output power level for the power amplifier and the feedback signal on a second input.

30. The modulation system of claim 29, further comprising means for selectively fixing the output signal of the integrator to a constant level during a data transmission phase of EDGE polar-lite modulation.

31. The modulation system of claim 21, further comprising means for generating a ramp signal, wherein the ramp signal is coupled to the second selectable amplitude modulation path to adjust the output power of the power amplifier during a ramp phase of full-polar modulation.

32. The modulation system of claim 21, wherein said combiner comprises a multiplier.

33. The modulation system of claim 21, further comprising a polar converter receiving base band data and converting it into the phase and amplitude components.