Efficient modulation of rf signals

• US 20060126754A1
• Filed: 01/07/2004
• Published: 06/15/2006
• Est. Priority Date: 02/20/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Itkin, Grigory, Varlamov, Oleg, Filimonov, Nikolai
• Granted Patent: US 7,724,837 B2
• Time in Patent Office: Days
• US Class Current: 375/296
• CPC Class Codes: H03C 3/40 using two signal paths the outputs of which have a predetermined phase difference and at least one output being amplitude-modulated
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• 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 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals
• 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

Coherent modulator architectures of wireless communication devices are used for the processing of modulated RF signals. The circuitry comprises a DC/DC converter (204) which serves as an amplitude modulator, different amplification stages (204, 206, 212, 214), a bypass path (215) to selectively bypass at least one (214) of a cascade of class C, D, E, or F power amplifiers (212, 214), and an automatic power control (APC) loop (220) that guarantees power stability over time and temperature variations. To increase the efficiency of the amplification procedures needed for an amplitude modulation, the slow (narrowband) high-level components (222) and the fast (wideband) low-level components (224) of the signal representing the magnitude (I x_Lp (t) 1) of an I/Q modulation state (x_Lp (t)) are amplified in separate stages (204, 206) and are then combined by sup plying the low-level components (224) to a power amplifier (206) whose gain is controlled depending on the amplified high-level components (222). At least one (214) of said cascade of power amplifiers (212, 214) can selectively be bypassed by a bypass circuitry (215), which is used for the sake of efficiency optimization. In the bypass mode, the DC power supply (V_bet) of the bypassed power amplifier (214) can selectively be switched off by means of a switch (SZ). It is used when the needed RF signal power is low and the driver PA (212) is able to produce enough gain.

Claims

1-22. -22. (canceled)

23. A method for I/Q modulation, the method comprising:

converting an in-phase (I) and a quadrature (Q) component of a complex-valued analog baseband input signal into signals representing a magnitude and a phase of I/Q modulation states of the complex-valued analog baseband input signal, respectively; and

combining the signals representing the magnitude and phase to generate a modulated RF output transmission signal,

wherein slow high-level components and fast low-level components of the signal representing the magnitude are amplified in separate amplifier stages, and wherein the slow high-level components and the fast low-level components of the signal representing the magnitude are combined to provide a combined envelope representing signal by supplying the low-level components to a power amplifier whose gain is controlled based on the amplified high-level components.

24. A method according to claim 23, wherein the slow high-level components of the signal representing the magnitude are amplified using a DC/DC converter.

25. A method according to claim 23, wherein the combined envelope representing signal controls a gain of at least a second power amplifier supplied with an RF signal modulated with the signal representing the phase.

26. A method according to claim 23, wherein the combined envelope representing signal controls a gain of at least one of a plurality of serially connected power amplifiers, and wherein a first one of the plurality of power amplifiers is supplied with an RF signal based on the signal representing the phase.

27. A method according to claim 26, wherein at least one of the plurality of power amplifiers is configured to be selectively bypassed.

28. A method according to claim 27, wherein a power supply of a bypassed one of the plurality of power amplifiers is configured to be selectively switched off.

29. A method according to claim 26, wherein the combined envelope representing signal is configured to be selectively dampened.

30. A method according to claim 23, wherein the high-level components of the signal representing the magnitude are represented by a ramp signal supplied from a baseband block to an amplifier.

31. An I/Q modulator configured to carry out a method according to claim 23.

32. A method for I/Q modulation, the method comprising:

converting an in-phase (I) and a quadrature (Q) component of a complex-valued analog baseband input signal into signals representing a magnitude and a phase of I/Q modulation states of the complex-valued analog baseband input signal, respectively; and

combining the signals representing the magnitude and phase to generate a modulated RF output transmission signal,

wherein a signal representing a power of the modulated RF output transmission signal is fed back to provide an automatic power-controlled (APC) loop, and wherein the APC loop is opened when the signal representing the power of the modulated RF output transmission signal reaches a defined nominal value.

33. An I/Q modulator configured to carry out a method according to claim 32.

34. An I/Q modulator, comprising:

a conversion unit configured to convert an in-phase (I) and a quadrature (Q) component of a complex-valued analog baseband input signal into signals representing a magnitude and a phase of I/Q modulation states of the complex-valued analog baseband input signal, respectively;

a combination unit configured to combine the signals representing the magnitude and phase to generate a modulated RF output transmission signal;

a first amplifier stage configured to amplify slow high-level components of the signal representing the magnitude;

a second amplifier stage configured to amplify fast low-level components of the signal representing the magnitude; and

a power amplifier supplied with the fast low-level components and having a gain controlled based on the amplified slow high-level components,

wherein the power amplifier is configured to combine the slow high-level components and fast low-level components of the signal representing the magnitude to provide a combined envelope representing signal.

35. A modulator according to claim 34, further comprising:

a DC/DC converter configured to amplify the slow high-level components of the signal representing the magnitude.

36. A modulator according to claim 34, further comprising:

a second power amplifier supplied with an RF signal modulated with the signal representing the phase and having a gain controlled by the combined envelope representing signal.

37. A modulator according to claim 34, further comprising:

a plurality of serially connected power amplifiers having respective gains controlled by the combined envelope representing signal,

wherein a first one of the plurality of power amplifiers is supplied with an RF signal based on the signal representing the phase.

38. A modulator according to claim 37, further comprising:

a switch configured to selectively bypass at least one of the plurality of power amplifiers.

39. A modulator according to claim 38, further comprising:

a second switch configured to selectively switch off a power supply of a bypassed one of the plurality of power amplifiers.

40. A modulator according to claim 37, further comprising:

a switch configured to selectively dampen the combined envelope representing signal.

41. A wireless transmitter, comprising:

an I/Q modulator according to claim 34.

42. A mobile telecommunications device, comprising:

an I/Q modulator according to claim 34.