Transmitter Apparatus and Wireless Communication Apparatus

• US 20070291873A1
• Filed: 01/11/2005
• Published: 12/20/2007
• Est. Priority Date: 01/27/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Saito, Noriaki, Tanaka, Koichiro, Tanabe, Mitsuru
• Granted Patent: US 7,684,514 B2
• Time in Patent Office: Days
• US Class Current: 375/298
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 1/0227 using supply converters
• 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: 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
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 2001/045 with means for improving efficiency
• 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
• CPC Class Codes: H04L 27/366 Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A transmitter apparatus that exhibits a high efficiency and that can provide a wide variable output control width. An operation of saturation mode is performed in the vicinity of the maximum transmission power. A large-power amplifier (12) is caused, by increasing and then fixing the input level thereof, to operate in a saturation state, while the amplitude component of a modulation signal in a range corresponding to an output power control level is inputted to an R-input terminal (33) to amplitude modulate the power supply voltage (VDD) of a power supply terminal (25), thereby performing a polar coordinate modulation of a high efficiency. An operation of linear mode is performed for a smaller transmission power. The large-power amplifier (12) is caused, by reducing the input level thereof, to perform a linear operation, while the power supply voltage (VDD) of the power supply terminal (25) is varied in accordance with the output power control level, thereby performing a transmission power control.

Claims

1. A transmitter comprising:

a quadrature modulation unit which inputs an in-phase component and a quadrature component of an input modulation signal and performing quadrature modulation;

a variable gain amplification unit which amplifies output of the quadrature modulation unit with a gain being controlled based on a gain control signal; and

a power amplification unit which performs power amplification of output of the variable gain amplifications unit,

wherein the power amplification unit has a linear mode for performing power amplification using a linear operation region in an input/output power characteristic and a saturation mode for performing power amplification using a saturation operation region in the input/output power characteristic, and

wherein, if transmission output power is equal to or greater than a predetermined value, the output level of the variable gain amplification unit is adjusted, the power amplification unit is operated in the saturation mode, and a transmission output control signal amplitude-modulated based on an amplitude component of the input modulation signal is input to an output control input terminal of the power amplification unit for performing polar coordinate modulation;

if the transmission output power is less than the predetermined value, the output level of the variable gain amplification unit is adjusted, the power amplification unit is operated in the linear mode, and a transmission output control signal of a predetermined level responsive to the transmission output power is input to the output control input terminal for performing linear amplification.

2. The transmitter according to claim 1,

wherein, if the transmission output power is at the maximum output level or in the proximity thereof, the power amplification unit performs the polar coordinate modulation and if the transmission output power is smaller than the maximum output level or the proximity thereof, the power amplification unit performs the linear amplification.

3. The transmitter according to claim 1,

wherein the power amplification unit comprises a power supply terminal used as the output control input terminal, and

wherein the transmitter further comprises a power supply driver for increasing the current capacity of the signal of the predetermined level or the signal amplitude-modulated based on the amplitude component of the input modulation signal and supplying power to the power supply terminal as the transmission output control signal.

4. The transmitter according to claim 1,

wherein the power amplification unit comprises:

a power supply terminal to which fixed power supply is input; and

an amplification circuit bias terminal used as the output control input terminal to which the transmission output control signal is input.

5. The transmitter according to claim 1, further comprising a transmission output control signal input section for inputting the transmission output control signal,

wherein the transmission output control signal input section comprises a DA converter for converting a digital signal into an analog signal, and

wherein the DA converter can change an operation clock and has an operation clock switch function for operating with a higher operation clock than that when the linear amplification is performed only when polar coordinate modulation is performed in the power amplification unit.

6. The transmitter according to claim 3,

wherein an input section of the power supply driver comprises an operational amplifier for waveform shaping, and

wherein the operational amplifier can change an operation current and has an operation current switch function for increasing the operation current as compared with that when the linear amplification is performed only when polar coordinate modulation is performed in the power amplification unit.

7. The transmitter according to claim 3,

wherein the power supply driver is a liner regulator.

8. The transmitter according to claim 3,

wherein the power supply driver is a switching regulator.

9. The transmitter according to claim 3,

wherein the power supply driver comprises:

an amplitude slice unit which slices the transmission output control signal at stepwise different voltage levels;

a plurality of switching regulators for converting the power supply voltage into voltages of stepwise different values; and

a switch group for selecting any one of the output voltages of the plurality of switching regulators.

10. The transmitter according to claim 1, further comprising:

a demodulation section for demodulating output of the power amplification unit; and

a control section for adjusting the timing of amplitude modulation when polar coordinate modulation is performed in the power amplification unit based on information of a demodulation signal provided by the demodulation section.

11. A wireless communication apparatus comprising a transmitter as claimed in claim 1.