Multi-mode envelope restoration architecture for RF transmitters

• US 20040052312A1
• Filed: 09/17/2002
• Published: 03/18/2004
• Est. Priority Date: 09/17/2002
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Matero, Jorma
• Granted Patent: US 7,123,664 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H03F 3/2176 Class E amplifiers
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

An RF transceiver having dual-mode envelope restoration architecture. In narrow-band applications such as GSM/EDGE, a switch-mode amplifier is used to provide an envelope signal for amplitude modulating the phase-modulated signals. To achieve required modulation bandwidth in wide-band applications such as WDCMA, an analog amplifier is used to provide the envelope signal. Furthermore, in the wide-band mode, the envelope modulation is applied through the base of an emitter follower while the collector voltage is scaled to achieve a desired power output in the amplitude-modulated signals.

Claims

1. A transmitter (100) for transmitting information in a modulated signal at least in a first carrier frequency band or a second, different carrier frequency band, said transmitter characterized by

a signal processor (112) for providing baseband data (210,212) indicative of the information, by

means (120,130), responsive to the baseband data, for providing an envelope waveform (232, 250) indicative of an envelope of the modulated signal, by

a phase modulating mechanism (116, PLL1, VCO1, 142, 144) for providing a first signal (242) in the first carrier frequency band and a second signal (244) in the second carrier frequency band, by

a first amplification device (A3, A4), responsive to the envelope waveform (232, 250) and the first signal (242), for providing the modulated signal (342) in the first carrier frequency band, by

a second amplification device (A5, A6), responsive to the envelope waveform (250) and the second signal (244), for providing the modulated signal (344) in the second carrier frequency band, and by

a band selection means (114) for selecting at least between the modulated signal in the first carrier frequency band and the modulated signal in the second carrier frequency band for transmission.

2. The transmitter of claim 1, characterized in that the first and second signals are phase modulated radio-frequency signals.

3. The transmitter of claim 2, characterized in that

the first carrier frequency band comprises a first range of radio frequencies and the second carrier frequency band comprises a second range of radio frequencies lower than the first range, that

the baseband data (210, 212) is provided in a digital form, and that

the envelope waveform providing means (120, 130) comprises a pulse width modulator (120) for providing the envelope waveform for amplitude-modulating the second signal.

4. The transmitter of claim 2, characterized in that

the first carrier frequency band comprises a first range of radio frequencies and the second carrier frequency band comprises a second range of radio frequencies lower than the first range, that

the baseband data (210, 212) is provided in a digital form, and that

the envelope waveform providing means (120, 130) comprises a digital-to-analog converter (130) for providing the envelope waveform for amplitude-modulating the first signal.

5. The transmitter of claim 4, characterized in that the envelope waveform providing means (120, 130) further comprises a pulse width modulator (120) for providing the envelope waveform for amplitude-modulating the second signal.

6. The transmitter of claim 5, characterized in that the envelope waveform (232, 250) comprises a first waveform component (232) and a second waveform component (250), wherein the pulse width modulator (120) provides the second waveform component for amplitude-modulating the second signal.

7. The transmitter of claim 5, characterized in that the envelope waveform (232, 250) comprises a first waveform component (232) and a second waveform component (250), wherein the digital-to-analog converter (130) provides the first waveform component for amplitude-modulating the first signal.

8. The transmitter of claim 5, characterized in that the envelope waveform (232, 250) comprises a first waveform component (232) and a second waveform component (250), wherein

the digital-to-analog converter (130) provides the first waveform component, and

the pulse width modulator (120) provides the second waveform component, said transmitter further characterized by

an emitter-follower device (T1) having a collector, an emitter and a base, wherein

the second waveform component (250) is provided to the collector of the emitter-follower device, and

the first waveform component (232) is provided to the base of the emitter-follower device, so as to provide an envelope voltage at the emitter of the emitter-follower device for amplitude-modulating the first signal.

9. The transmitter of claim 8, characterized in that the second waveform component (250) is scalable so as to achieve a desired output power in the modulated signal (342) in the first carrier frequency band.

10. The transmitter of claim 1, further characterized by

means (112, 132) for controlling power of the first and second amplification devices.

11. The transmitter of claim 3, characterized in that the first carrier frequency band comprises a frequency band substantially at 1900 MHz.

12. The transmitter of claim 3, characterized in that the second carrier frequency band comprises a frequency band substantially at 900 MHz.

13. The transmitter of claim 3, characterized in that the first carrier frequency band comprises a frequency band substantially at 1900 MHZ for wideband code-division multiple access applications, and the second carrier frequency band comprises a frequency band substantially at 900 MHz for GSM applications.

14. A method of envelope restoration for information transmission in a modulated signal at least in a first carrier frequency band or in a second different carrier frequency band, said method characterized by

providing baseband data (210, 212) indicative of the information, by

providing an envelope waveform (232, 250) indicative of an envelope of the modulated signal based on the baseband data, by

providing a first phase modulated signal (242) in the first carrier frequency band and a second phase modulated signal (244) in the second carrier frequency band, by

providing a first amplitude-modulated signal (342) in the first carrier frequency band based on the envelope waveform and the first phase modulated signal and a second amplitude-modulated signal (344) in the second carrier frequency band based on the envelope waveform and the second phase modulated signal, and by

selecting between the first amplitude-modulated signal and the second amplitude-modulated signal for transmission.

15. The method of claim 14, characterized in that

the baseband data is provided in a digital form, and that

the envelope waveform comprises:

a first waveform component provided by a digital-to-analog converter (130) for amplitude-modulating the first phase modulated signal for providing the first amplitude-modulated signal, and

a second waveform component provided by a pulse width modulator (120) for amplitude-modulating the second phase modulated signal for providing the second amplitude modulated signal.

16. The method of claim 14, characterized in that

the baseband data is provided in a digital form, and that

the envelope waveform comprises a first waveform component provided by a digital-to-analog converter, and a second waveform component provided by a pulse width modulator, said method further characterized by

an emitter follower device (T1) having a collector, an emitter and a base, wherein the second waveform component is provided to the collector of the emitter-follower device, and the first waveform component is provided to the base of the emitter-follower device, so as to provide an envelope voltage at the emitter of the emitter-follower device for amplitude-modulating the first phase modulated signal for providing the first amplitude-modulated signal.

17. The method of claim 16, further characterized in that the second waveform component is scalable so as to achieve a desired output power in the first amplitude-modulated signal.

18. A transceiver (10) adapted to operate at least in a first carrier frequency band or in a second, different carrier band, comprising:

an antenna (102),

a transmitter (100) operatively connected to the antenna for transmitting signals, and

a receiver (150) operatively connected to the antenna for receiving signals, characterized in that the transmitter comprises;

a signal processor (112) for providing baseband data (210,212) indicative of the information,

means (120,130), responsive to the baseband data, for providing an envelope waveform (232, 250) indicative of an envelope of the modulated signal,

a phase modulating mechanism (116, PLL1, VCO1, 142, 144) for providing a first signal (242) in the first carrier frequency band and a second signal (244) in the second carrier frequency band,

a first amplification device (A3, A4), responsive to the envelope waveform (232, 250) and the first signal (242), for providing the modulated signal (342) in the first carrier frequency band,

a second amplification device (A5, A6), responsive to the envelope waveform (250) and the second signal (244), for providing the modulated signal (344) in the second carrier frequency band, and

a band selection means (114) for selecting at least between the modulated signal in the first carrier frequency band and the modulated signal in the second carrier frequency band for transmission.